It sounds like you had to deal with an industrial-strength toxic situation. I feel for you.

My SKs, especially SD63, experienced the fear of loss of resources.  Though DH paid his CS and, in addition, went over and above with everything imaginable, including buying BM a car, it was never enough in SD's eyes.  I think the fact he was living with me and my 2 bios meant that something was being taken from her.  In reality, divorce DOES mean loss of resources.  I don't know a way around that.  The step-sons seemed to either feel the situation was neutral or that things were better because DH made a .much bigger effort to do things with them.  For my sanity, he took all 5 kids out all day every Saturday..  He. bought SD a horse and they all spent a lot of time at the ranch where the horse was stabled. They fished, rode motorbikes, etc.  But SD's jealous resentment showed itself by her constant surveillance of our home and my possessions. It's never really stopped.

And while I agree with it all, I'm so done with DHs kids and trying to figure them out. ADULTS. In their late 30's and 40's. I have countless hours of research, book reading, pod cast listening, therapy, etc. on this subject, trying to understand. I'm done. Again, DH's kids are WAY into adulthood. Grow the F up. 

My interactions with DHs kids are minimal, short lived, civil and superficial. I'm kind but very distant and refuse to discuss anything personal or deep with them. Today, I'm very happy being DHs wife. May his kids be happy in their dysfunctional worlds. They've done all the damage here I'm going to allow. SMH

Wow. #Truth. I will be rereading this. 

You will be repayed in life's.  with goodness .   My SK birth father rather drink then being a father.  I was the only father they knew. Our relationship with my SO wasn't all roses. I don't think I was SP material.  I did a lot for these kids out of my kindness .  I hope I am being repayed

and polluted end of his gene pool except intermittently. We were the CP side of the equation, and visitation was dispersed with wide separations in those visits.

That, and my give a shit about the why of chosen shit behaviors is absolute zero.  I do not care why. I care about what. What they do. Why they do it makes zero difference to me. None. Zip. Nada.

I do care about what they do. If they are reasonable, great. If not, it is instantly game on.  I bring the application of abject misery to bear immediately. I apply pain, explain the pain and the conneciton to their choices. Lather, rinse, repeat while amplifying the misery for repeat bullshit.  They either learn to life a decent existance in my life or they learn to writhe in pain and misery separate from my life. Their choice.

maladaptive inflexibility What a great term.  Though IMHO it is just more excuse based bullshit that gives toxic people some justification for their bullshit.  I think of it as Malbehaved Toxicity or Malbehaved Toxic Manipulation.  Which is purely the choice of the maladapted inflexible people.  Broad society runs for some excuse or reason for idiots to be idiots rather than just simply labeling them as what they chose to be and applying the consequences that they earn with their chosen behavior.  Dr. Phil hits the nail on the head withthe patent "How is that working out for you?" question he tends to ask every moron he makes money from on his shows.  Smart guy.

The 5 whys/core fears of those embracing the disorder syndrome of the moment fits the SpermGrandHag like a cheap worn out dirty sock.  Which is what she has always been the subhuman example of.

IMHO fear is a choice. So, apply consequences for those choices rather than giving a shit about why they make those choices. 

In the interest of KISS.

1. The Fear of Abandonment. - No doubt your DH's X abandoned the marriage by being toxic. Though no one is entirely blameless in a divorce, invariably the toxic half of the blended family equation bears the majority of the fault in the end of the failed initial family.  So, her choice was effectively to abandon decency and she physically lives the consequences of that. Leave her twitching at the side of the road while getting on with living your best life. Applause to DH and to you for facilitating BM's choice. Let her own both that choice and the pain. The SGH formerly in our life had to have her minions surrounding her.  DW escaping and taking her then infant DS with her was the ultimate affront to the Hag. I made sticking that fork in her and rotating forcefully one of my fondest hobbies for our near two decades under the CO.

2. The Fear of Not Being SPECIAL. - They aren't so no big deal.  Special is not a state of mere existence. It has to be continually earned and demonstrated by action. It is not something attained at birth and retained for eternity. They are not special so giving them that clarity is what we owe them. So, deliver on that message and make them live what they have actually earned.  Pointing out in repeated great detail exactly what makes then not special.  With a logical connection to what they could do differently to attain special-ness. Lather, rinse, repeat. Pain or pleasant existence associated with reasonable behavior.  Make this a clear choice for them and deliver the results that they earn.  My SS is special. We raised him with standards of behavior and standards of performance that built him to perform to the special standard.  Interesting actually being special is Kryptonite to those who are not.  Sadly, the draw of toxic can prevent special from sticking.  But, when a SKid attains and maintains special, the shallow and polluted end of their gene pool will evaporate away from them in an expedited manner and the special COD will be better for it. Though not specifically a COD because my DW and the SpermIdiot were never married, this progression of lessons as he was growing up while painful for SS, is in large part why he is living a good life Vs the shit puddle of toxic effluent lives that his three younger Spermidiot spawned half sibs are living.  I feel for SS as this hurts him to his core. I also feel for the half sibs. Though they have made no effort to deviate from the toxic path that everyone in the SpermClan follows generation after generation.

This was a message that my SS received from his middle school band director. "There is nothing appealing about you. Not your personality, not your performance, nothing. You could be truly great, but you choose to be unappealing on every level."  That destroyed SS.  He was so upset when he got that message. He came home all torn up over it. Of course mom instantly went into poor baby mode and wanted to put out a hit on the band director. I engaged SS in conversation, drew out of him what he had been doing when the director gave him that input, and then agreed with the band director.  Not real popular with my bride or our kid, but..... facts are neither good nor bad. They are merely facts. What one does with those facts is what determines if they are special or not.  SS is a truly wonderful man. An adult of character and honor, standing in his life, profession, and community.  He figured out how to be special and earns it every day. Special is not a one and done coronation.

3. The Fear of Abandonment. - With the exception of a true deadbeat, there is no abandonment.  The lesson this is IMHO delivered by actively requiring compliance to the CO, visitation schedule, and CS payments. Then when the toxic opposition shit parent plays these games, the kids get a full dose of the recounted facts of the situation and of your DH's contact, pursuit, and involvement.  Then when the SKids age out from under the CO they get the scruff of the neck, scrubbing of their noses, and swat to the rump message that they are the ones not investing. Lather, rinse, repeat.  Regardless of their investing or not, they have to see DH and Toaster living their best lives together. Whether the failed family progeny participate in that or not. Once they age out from under the CO, they own half of the contact effort.  They don't play, they don't get to cry that daddy abandoned them without the the firm message of the scruff of the nect, nose in their stench, swat to the rump review of their crap. Over, and over, and over again.  In our example. The Spermidiot did abandon SS. For the 16+ years of the CO never once did he call to speak to SS. Not once did he or anyone else in the SpermClan visit SS in SS's world. No attendance of graduations, award's ceremonies, performances, tournaments, etc, etc, etc... not one. Not even a graduation card.  SpermGrandHag on the other hand, she toxicly engaged until SS aged out from under the CO, at which point she dropped off of the planet. Though she still tries her guilt crap. She and SS's aunt stalk my FB and when someone comments about us being in SpermLand to visit my ILs they start blowing up SS with the guilt press to visit them, stop by to see them, etc, etc, etc.... For these types. The best thing a confident person can to is... abandon them and deliver to those fears with the most clear message possible. They do not matter. Buh-bye.

4. The Fear of Losing Resources - Those resources were never theirs to lose. They are the NCPs resources. Always were. Always will be. When the CS order ends, no loss, no harm, no foul.  Though in our blended family journey under the CO, SpermGrandHag and SpermGrandPa defended that pittance in CS like it was the crown jewels.  Before SS's first birthday DW went to court for an order of paternity and for CS. Both were granted.  CS was $110/mo.  DW was officially named the CP with full physical and legal custody.  No visitation was set.  So, SpermGrandHag started her 17yr payment of her idiot son's CS to my SKid.  This caused SpermGrandPa's head to explode since he was of the mind that his idiot son should pay for his own spawning hobby. A few months after the Paternity/CS order was issued SpermGrandHag heard that DW was dating someone out of State at university and filed a custody suit.  That often delayed hearing happened a few days after we married.  Full physical and legal custody was upheld for DW, 7wks of visitation was set for the Spermidiot in lieu of the full custody they sought, and CS went up from $110/mo to $130/mo which SpermGrandPa very loudly complained about when the Judge issued the ruling. IMHO your DH's spawn need the full spreadsheet resource review showing the countless $Thousands he paid to BM over the years, a full review of the CO, every Custody/Visitation/Support record, all of the court reporter transcripts, the history of the demise of his and BM's marriage, etc, and then he should tell his spawn to demand that BM account for where their money is and since she obviously doesn't have it, what she spent it on and when they will get it.   It is called Child Support, not XSpouse Support.  Kids need the facts. In an age appropriate manner.  Though we were the CP side, DW went full CPA on the opposition and made sure SS knew just how much CS was, showed him the sliver of the pie chart of expenses that it covered, and gave SS the information he needed to shut down the bullshit from SpermGrandHag that CS was taking food out of the three younger half sibs mouths, buying us houses, cars, sending us on nice vacations, buying SS nice clothes, things, etc... and the half sibs could not have those things because of CS.  Even after SS aged out from under the CO, the Hag tried to demand that SS repay the 17 years in CS. Because he knew the facts, had his CPA mom's spreadsheet showing our $millions in income over the CO  years Vs the pittance in CS paid, he was not tolerant of that demand. His clear NO!, changed the Hags tactics into quilting him to direct pay roll withhold part of his  pay to help support his younger sibs.  NO! to that one to. That was the final straw for them as anything in SS's iife and he asked me to adopt him not long after that.  We made that happen.

5. The Fear of Being Exposed- The duty of the quality side of the equation is to make this a reality rather than just a fear. Expose them. Full frontal, ass baring, in everyone's face fact based reality. The SKids in particular need this to happen or they are forever doomed to be at the not so tender mercies of the toxic, shallow, and polluted end of their gene pool.  We made this a lynchpin of our 17+ year defense against the dark arts perpetrated by the SpermGrandHag. Ultimately we had Her depravity highlighted in all of the areas in her life. To her children, GKs, work, cult, and community. If they had nothing to hide they would have nothing to be afraid of. So, give them the mercy killing of baring their asses and making their community, family, church, work, etc.. fully aware of what and who they are.  Using every legal, social, and financial tool available. Then sitting the kids down and having the hard discussion on whether they want to be quality people or join the toxic parent in wallowing and splashing around in the noxious effluent of a reeking life that the toxic parent chooses to live.  Though it certainly may be interpreted that this is far from kind. IMHO it is the greatest kindness that a caring, quality parent can give to their children when dealing with a tragically and toxicly flawed X.

Facts, facts, facts, facts, facts.  Start when the SKid asks the first question about what "Parent X" said and build on it in an age approriate manner for the rest of times. Over, and over, and over again.  Never destroy the records.  Make sure that the Kids have a full copy of every sordid detail. The CO, the court reporter transcripts to make sure that every word spoken in court is known, every journal, every arrest record, every PI investiation report, every supplemental jurisdictional rule, every State regulation, every, sordid detail.  If a SKid is going to wallow in the shallow and polluted gene pool of the toxic parent, they should have to do it with full knowledge of the facts.  

This is of course not without consequences for the SKids.  They don't escape entirely baggage free. Even whhen they choose an exempliary life.  My SS-32 knows that his SpermClan are people who he is supposed to love and respect. However, he does not respect them because they do not earn his respect. They really never have.  For many years during the CO and for a few years after he aged out from under the CO he maintained that the if the SpermGrandHag had not raised his three younger sibs they would never have had any life at all.  When he came at full speed face frist into clarity that she was the common denominator of how deplorable his Spermidiot is, and the root cause of his three sibs either being on the dole (SPeridiot spawn #2), in prison (Spawn #3), or on the path to prison (#4) it crushed him.  The hag gave him that clarity far more effectively than his mom or I had ever been able to demonstrate via the facts. Though his knowledge of the full historical facts IMHO gave him the knowledge needed to finally gain clarity that the Hag is the root of all SpermClan evil.

But, I as usual, digress with far to much verbal sputum.

maladaptive inflexibility - Thanks for expanding my vocabulary and introducing a powerful concept.

All IMHO and experience of course.

First, thanks for your kind words about my post. It was inspired by things I've read here. i think we often "feed" one another in a positive way! 
 

Fear of change. Fear of betrayal. Fear of losing the life they once knew, even if it wasn’t perfect. When a stepparent steps in with kindness, it’s not always seen as a gift—it’s often viewed as a threat. A reminder that things are different now, that their failed family is forever gone, and that accepting kindness might mean letting go of old loyalties or admitting that the “evil stepparent” narrative isn’t quite accurate.

Yes. And this is spoonfed by the dysfunctional BM. It was clear to me who had the problem with DH dating. I strongly felt she was transferring and channeling those feelings to and through the skids, never seeming to comfort them when they finally expressed their fears/took on her panic. What a horrible selfish thing to do.

Once the skids were all in, they created a false narrative which turned out to be a self fulfilling prophecy, as their poor behavior over feeling "abandoned" (which they were not) and making me out to be the bad guy pushed their father away,
 

For some skids, rejecting kindness isn’t about who the stepparent is—it’s about holding onto a past they’re afraid to release. Its maladaptive inflexibility.

DH has always told me that it was never me. Whoever he would be with would be the scapegoat,  blamed for "breaking up the family." 
 

Sick. 

Lol at this title though *lol*

Failed "first" family is a cult, a gang, and a d0mestic t3rrorists organization all rolled into one

The Disneyland dad I used to deal with has a conniving ex wife who realized when she couldn't use her worn out cavernous crotch to control Disney Dad...she resorted to using her "mini" footsoldiers to enact her schemes

She kept a mobile "B*tch Beck and Call" service operating 24/7 with Disneyland dad as the sole unpaid employee and her/her spawns as the paid-with-child support owners/operators 

When we lived together she moved her trifling a$$ 7 minutes away and once I got tired of her games...I proposed moving to another state and when he stupidly told her he was searching for out of state jobs she pulled the woe is me "I need help with these kids" ... like b*tch sit down, take your child support, ask your plethora of family or whoever, raise your kids to be independent for their age instead of using Disney Dad, and set your kids on the plane during holidays and summer like most divorced single moms with out of state NCP do

The fact that dude procreated multiple times with such low class inept person was really baffling 

I will be saving this post to refer back to frequently. Great insights.