DH and I got married when SD was in her late teens.  She was mean and lazy then but nothing like when she became an adult.  I can give you a big tip:  Don't wait until it gets really bad to take action.  Your marriage should be top priority for both of you.  You should give the image of a united front.  DH must never be allowed to throw you under the bus, discuss your marriage with the skids or make unilateral decisions without conferring with you first.  Never allow Skids to get obnoxious, rude or disrespectful.  Nip it in the bud right away.  Establish boundaries and don't budge  from them.  Do not try to make them like you.  If they treat you with respect and tolerance you will be very lucky.  

If your steps are lazy, disrespectful, entitled and needy as children and they are over the age of 3 then be prepared for them to stay that way.  It only takes one parent with lousy parenting skills to create this, usually via PAS or Disney parenting and unless that parent changes their ways, nothing will change.  Sorry to be so negative but I have been with my DH for 19 years and my  3 steps are now in their mid to late twenties and are still lazy, entitled, needy and to varying degrees disrespectful.  So good luck.  

I had my SS-26 from the week before he turned 2yo until he aged out from under the CO at 18yo.  

He was not a bad kid at all and has been a pretty great adult as well.  Did he get better?  Yes he did.  But, his mom and I had firm standards of behavior and performance that we raised him under.  He has carried those on into adulthood.

He asked me to adopt him when he was 22. We made that happen.

If your waste of parental skin SO has created and tolerated these POS ill behaved toxic crotch nuggets it is highly unlikely that they or he will change significantly between now and when the Skids reach a toxic adulthood.

What is IMHO a non-negotiable is that as your SO's equity life partner you are also an equity parent to any children in your home regardless of kid biology.   So, if your SO won't step up and parent then you do it.  If he does not like how you parent and discipline his ill behaved crotch nuggets, he can STFU and have your back or he can step up and get it done before you have to.

If he nor you will change the disciplinary consequences for kid toxic behavior then it will just get worse as time goes by and it will be beyond description when these toxic spawn reach adulthood.

Good luck.

Take care of you.

 Skids were pre pubescence when DH and I started dating, and are in their mid to late thirties now.

Things have ebbed and flowed over the years, but never gotten any better. Generally, the skids only make contact (rarely) when they want something (either $$ or some kind of "better" relations), but because none of the players have gotten any professional help, things never evolve. You can't fix something if you don't know how or lack the proper tools. My DH has pretty much dropped the rope. His kids are too much like their mothers, and were raised to only take, take, take. Without me doing all the work, it's just not worth it to him to engage in the drama.

It all begins with the basic parent-child relationship. If that is dysfunctional, or if the other parent goes to war against your SO, there's little hope for a step parent to have successful relations with the skids.

I met my DH when his daughters were aged 5 and 7, they are now 22 and 24.  They were awful all the way through to their late teens, and DH didn't have my back in demanding that they treat me (and him) with respect.  However, he had a bit of a road to Damascus moment back in 2013, and since then has required a lot better behaviour from them.  I have also changed in that I will not stand meekly by and be treated like shit any longer.   

SD24 is still an entitled freeloader, but at least she is respectful towards me, and so is her sister.   I totally agree with the advice given by sandye21 as to how to proceed.  

Mine isn’t an adult yet but have already laid down rules with DH. SS will go to college, get good grades if he wants to live with us for part of it (please don’t pleaseeee!). If he doesn’t go he won’t live here. He can go figure out how to survive on minimum wage at McDonalds. (My guess is this will be what he chooses). Also said, since we likely will have at least 1 if not more babies in the house then, that I won’t have a 20 year old, coming and going at all hours, waking the kids up, friends constantly around, situation.  If he gets to live here he can consider it a place to sleep, eat and study. I am not having him interfere with babies sleep schedules, arguing or any of that crap. 

Husband mentioned he may sling shot back at some point and I said only if it is something out of his control, (laid off and no work is available, injured, or something) and with the same rules and it will be deeply discussed with ME before it is even considered. 

Lord help me. 

I'm dealing with a 26 year old and 29 year old.  Thankfully, the miniwife/26 year old moved to TX to be closer to her mom so that her mom could pay for everything.  She is 13 hours away and it has been AWESOME!!!  The 29 year old is still an out spoken bitter problem BUT my DH has asked her to be more mature and kind if she plans to be around us/house.  She is so bitter and hateful she will be single for the rest of her life no doubt.  When we were first married I let probably too much slide becuase it was an adjustment for all of us.  However, I feel they are mature enough now not to act like they are still 8.yrs old.  Not anymore - I think I sent them into shock when I stood up for myself. The 29 year old doesn't come around much.  Of course, it is my fault but at least I'm going to earn that badge this time.  I have done nothing to them but disengage and took the control out of their hands as to when they could ignore me or disrespect me.  They can't stand it.  They have also shared with me that the house is their house - No way chickies.  I pay half and you guys are out on your own and are considered guests now.  It has recently been shared with me that I am not family.  I told them that theory works for me!  They were ready to argue but I didn't go there.  Mostly because I am fine with that thought.  But my DH is family and they will have to adjust.  The 26 year old has a problem with recognizing boundaries - I caught her in the act of taking some of my clothes and tried to get them in her suit case.  Called her on that right away and her Dad was present and supported me.  I have since put a lock on our bedroom door and use it when she visits.  Thank goodness she isn't able to visit much. 

I thought once they got past 21 at least we would grow up a little bit and things would get better.  I figured that they would be moving on with their own life and my DH and I could move on in ours.  Boy, was I wrong.  There is nothing like seeing a 29 year old throw a temper tantrum.  I can't wait to see how Thanksgiving/Christmas go - UGH.  If my extended family was closer I would just go over there.  However, they all live 7 hours away....Oh the joys.  

when i met hubby and he was about 16.5 when we married. Bio mum had kidnapped the 2 daughters then aged 9 & 19 and went awol. She cut off contact and the sd re-initiated contact with hubby mid last year.

did the whole sob story how he moved on, had a new wife, new family. They abandoned him and tried to make him guilty. They said they knew their mum lied to them about many things but hubby had to get over it.

there is and never will be an apology from them for anything. Ts just blame everyone else and twist it to make them seem innocent. Ss is the worst, he enjoys emotionally abusing people and laughs about it.

lucky my inlaws know hubbies kids with ex are dysfunctional just like narcissistic bio mum and the pas she brainwashed the kids on.

Since ss was the only one living in our home on university breaks i told hubby last year i had enough. It got to a point where we have 2 toddlers with important things to do like go to the clinic for vaccinations and grocery shopping which we always did as a couple. Hubby decided to disappear all day from 11am - 8pm on a weekend to play taxi for his lazy kids and treat them to lunch at a shopping mall. There was no asking me how are the kids? Have you eaten or do you want me to get something, groceries were running super low and i felt so abandoned by hubby and tossed to the side.’

i told him i’d had enough because skids never maintain contact but suddenly he drops everything for their scraps

breaking point for me was for our 4th wedding anniversary hubby said he was so busy that weekend (3 months in advance i checked) and said closer to the date he will find out which weekend he is free. 2-3 days before anniversary ss20 messages hubby he is free that weekend if we wanna take him and his sisters (sd14 &23) on holiday

hubby messages me instantly from work asking where i wanna go and to buy airplane tickets. Trust me he didn’t get a pleasant reply. I told him his kids sit there in awkward silence, they non stop talk about bio mum and stepdad and pretend we aren’t there, they never maintain contact, treat everyone like shit and now hubby wants me to spend our 4th wedding anniversary being treated like that.

i told him to go on his amazing holiday and i’d fly overseas home with our toddlers on hubbys credit card, hubby refused to go on holiday and told me it was torture having to spend time with them. He knew they treat everyone bad and going out of their way to remind hubby that bio mum exists when she is long gone from hubbys life.

it wasn’t till early this yr hubby had enough of as excuses for not doing chores, emptying trash etc and just being a total dick!! Hubby put his foot down because i had told him i wanted a divorce and he knew i would get sole custody of the kids since due to his job and work hours, he would not be able to care for them. That made hubby snap into reality that ss and sd’s had made life just miserable for everyone

now hubby rarely messages his kids, he ignores them and hubby is under strict instructions he doesn’t plan anything concerning quality family time unless he’s discussed it with me. Skids do not treat their dad as family so if hubby needs to disappear for a whole day with skids he should be able to spend a whole day dedicated to our kids on weekends for example. 

I felt my husband made executive decisions concerning our time and us being present without discussing with me and i didn’t feel like an equal partner/spouse of his. Its enough having stepdaughters thinking they can lecture me or go above me regarding the parenting of my toddlers, i will not be treated like beneath my husband with everyday life.