Who cares?  That's what true disengagement means.  You pay no more attention to how these two turn out that you do to some stranger's kids you've never met.  They have parents who are responsible for raising them.  Quite frankly you have virtually no influence over them good or bad.

It's time for you take control back of your own home. If SD14 raises the volume of the TV so no one can hear you, you turn the TV off.  These kids are not the ruler of the household. Do not buy them a thing; then you won't need to worry about them throwing it away.

If they cannot do three simple chores and they liken it to one of the worst tragedies in humankind, then make sure girls have zero privileges while they are there.....no internet, no special food, nothing.

Make your master bedroom, or another part of your household, into your own private oasis that you retreat to when they are there.  They are not allowed entry into this oasis. They are your DH's sole responsibility - he is the parent and you owe them absolutely nothing.  If your DH is upset by this, then you know exactly why he is with you in the first place - nanny to his kids he does not want to parent and his personal Helper/Bedwarmer.

If they turn into prostitutes, drug addicts, have eating disorders, it will somehow be your fault anyway. You could be doing everything for them and it would not matter.  You are not responsible for how they turn out; their father does not know what to do with them and does not seem to care enough to find out how to be a good parent.

Ignore them and learn to stop caring. If you are not able to do that, you may need to leave your fiance.

Some are able to make peace with the reality that their SO is a great partner but a terrible parent. (I have)  If you can disengage fully so his kids dont affect you, still love and respect him, and you both are committed to this and to moving forward, it can work. The risky part, however, is you're gambling on an unknown. Is your SO loyal to you? Would he be willing draw hard boundaries with his daughters, even if it means angering and possibly estranging them?

There's a lot of gray area to explore. You could try Living Apart, Together; him exercising visitation outside the home; you leaving during visitation; you lacing up your b!tch boots and not tolerating bratty behavior, etc.

I think I'd try complete, full disengagement first. Give yourself permission to be done with these feral girls. Done. Over. Spent. They don't like you, likely never will, and there's nothing wrong with removing them from your life. It's how you do it that counts. No big declarations or emotional scenes, just remove them from your life. 

It's not wrong to

Are these girls able to treat other adults like humans?  If they can do that, then they can treat you better.  If so then you need to ask daddy what makes you so special ??  Marry him? not the way things are now.  Each in their own way are walking all over you, treating you like crap.  It really won't change much if you marry.   That marriage certificate has a way of making disney daddy's get worse. Plenty of stories around here about that.  

Date him.  See if he can make inroads with his girls to act like better human beings.  

 “Marry him? not the way things are now.  Each in their own way are walking all over you, treating you like crap.  It really won't change much if you marry. “

Helena, you’ve been around ST long enough to know this is spot on. Fiddle with the deck chairs, but don’t marry the Titanic unless/until your particular skid problem has been resolved. Female skids especially tend to ramp up after daaadee remarries.

It won't harm the skids to disengage, because you shouldn't be doing more for them than their parents anyway. Your role is only to support your SO in parenting, and most skids have plenty of extended family to aid in that. They don't like, appreciate, or want you in their lives, so stepping back makes space for things to be as they are supposed to be. Ideally you just fade back, allowing your DH and skids to sort for themselves. No harm, just taking the target off your back by taking back your own life and leaving them to learn the life lessons they're supposed to.

You have agency. You can make choices and put up boundaries to protect yourself and demand the respect you deserve. I didn’t realize this until I’d been doormatting for almost two decades. We really do teach others how to treat us, so until you find a way to stand up for your needs, things won’t get better.

All of these above! You will get blamed for everything that goes wrong in these people's lives from now on- that is the reality of Steplife, so you have to ask if you can bear that burden- otherwise I would try living apart and see how that goes... that's what I would have done if I'd have realised.

I'd say helpful to all parties, given my experience, long term. It has been a huge relief for me and my life is so much better now that I took myself out of this exclusionary nastiness. But if you are not married to this man now, step back and think about what is to come for you. At least you are seeing this ahead of marriage and reality is rearing its ugly head.  After marriage, inbread jealousy only intensifies to the point you are the only one hurt and eventually will do anything to get out of step h...ll. No man is worth being abused. Taking yourself out of the mess brings you the most emotional peace, and over time, the longer this sickness is removed from you, the better you feel.

Besides, if you have a doormat man, what choice do you have? One way or another, you have to remove yourself from it.

At least your DH doesn't tell you to bugger off... just that he doesn't know what to do about it.... which is a great entry point into talking about what he could do... you could make suggestions, you could talk about trying to do certain things... you can take the opportunity to drive the point home that they behave that way because they're able to

Brats.  I rarely post anymore because it is a pain to log on each time I read the site but the girls comments about doing three chores being like a concentration camp really irked me.  

Your profile says you are in Texas...it is a bit of a drive...but the last trip I would ever take with these two spoiled girls is to Washington DC.   Tour the sites...drag them around to all the war memorials...then take them thru the Holocaust museum on a guided tour...go thru the museum every day you are there on the trip.  Clearly they need educating on what a concentration camp looks like.  Do not tell them this is the purpose of your trip.  Just do it.  If this is not feasible...get movies, documentaries, and books on the subject.  Require that they give a report.  No other fun summer activities until it is done. No internet, no WiFi, no phones until it is done.  Your DH needs to step up and make this happen.  Then he needs to read some parenting books or take a class.  

You meanwhile can sit in your living room and enjoy your tv.  If that living room is shared by DH is up to if he steps up and does his job.   

It does not get better on its own.  Getting married does not make it better.  You have tried long enough.  Make your own happiness now.  

If one of my bios compared chores to a concentration camp, they'd never hear the end of it from me.  Oh boy.  The unending sarcastic torture they would receive from me would give them all mental breakdowns.  

"OMG, you changed the TP roll??  Are you OKAY???  Did it trigger memories of your time in that concentration camp during THE HOLOCAUST?  You poor thing!  Are you IN PAIN????"  Nonstop.

I would also refuse to do any favors, stating that doing anything I don't want to do triggers my PTSD, because of my time in Auchwitz.

Who cares what the toxic crotch nuggets think or if it will harm them if you disengage?  Do what works for you.

I am not a proponant of disengagement. Rather I am a all about full on direct confrontation of any unacceptable behavior from Skids, spouses or the blended family opposition.

Fortunately the only major issues were with the SpermClan. My bride and I have always been mostly on the same page, the Skid was always pretty good aside from the usual teen boy brain fart stuff, and destroying the SpermClan was just plain fun.

Good luck.