Yes, parents do sometimes give up the fight for their own mental health - and there is nothing wrong with doing it. You can only fight so hard for so long without damaging yourself emotionally and financially. The therapist that was seeing SD12 (at the time) told DH to quit fighting to see her. She said he was doing more damage than good to the relationship and it would be better to let her go - for the sake of both of them. He did it and she gradually came back around. (It didn't last, but that is a whole other story...)

There is nothing wrong with at least "pausing" the fight. While I tend to think parents should enforce visitation, in your case, and given their ages, I don't see anything wrong with you not forcing visitation for awhile. Take a break from the stress and see what happens. Maybe they will see that they do miss you.

You are in a tough spot. Your current DH is not terribly supportive and you have issues w/the skids - it has to be terribly difficult to also have problems with your own kids. Do what will bring you some peace, and don't feel guilty for doing it.

Im sorry your going through all of this, it would be extremely draining to worry about this day in and day out.  But , I think you actually need to stop worrying about what all these other people are saying ,, stop worrying that his house has may have better things like cleaners etc , stop worrying and trying so hard to impress your kids ,, stop worrying that you think things are never good enough for them at your house,, just STOP all of it.  All you can do is be the best mum you know how ,, be a supportive mum , be a mum who listens and pays attention when your kids speak, be a mum who is reliable etc ,, you dont need to have fancy things to achieve all this.  I understand your kids may not see all this now ,, but as kids get older and become adults , they will see it ,, regardless of all the bad mouthing that happens about you,, as long as you dont ever bad mouth thier father / stepmum etc.  As they get older they start to realise and notice these things ,, they notice where stability comes from and that your always there for them no matter what.   My son is now 18,, but i was a single mum for many years whilst my son was young growing up ,, his dad was repartnered and they were always doing fun stuff together, the stepmum didnt work so she had time to stay at home and bake cakes etc, they were able to buy him fancy gifts so my son loved going there and never wanted to come home after the weekend and would cry and cry when i had to pick him up,, he would tell me he wanted to live with dad but i would soldier on with a fake smile on my face.  Being a single mum with virtually no money to spare , i always made sure my son was in a stable enviroment and we spent time doing things that didnt need money , like building cubby houses in the living room and having campouts etc ,,, as my son started to get much older he started to realise thats dads house was good to have fun at and get gifts but when it came down to the hard stuff , his dad and stepmum couldnt be depended on, they were alwasy to busy.  My son barely sees his father now , only on special occasions like xmas and fathers day,, still has a great time going there but knows where the real home is.   Keep soldiering on with a brave face and just be the reliable approachable parent who never tries to alienate them for the others but is always there no matter what 

Curious how you know all the negative things your ExH, ExBF, and the neighbors are saying about you? Are your daughters relaying it to you? 

I'm sorry, this is textbook parental alienation, as I know you are aware.

I wouldn't suggest giving up though my DH eventually did - but only when SS refused to come over.  I'd instead try to focus on rebuilding your relationship with them as much as you can, while not taking the alienation personally.  I know that's hard to do, but they are being fed a pack of lies by your XH.  If I remember (sorry if I'm wrong), you had an affair with your current DH, and I'm sure your X uses that to play the victim with the kids and everyone else. And fuel their anger that you broke up the family and left them.

Can you get into some kind of family therapy with them? Are both kids acting exactly the same, or is one less susceptible to the alienation?

I do know how hard this is - at the very least, find your own therapist to help you sort it out. But I wouldn't give up your time with them if you can stick it out. Try to grow a thick skin and remember that they are being manipulated, and deep down, they love you and need you very much.

You said it yourself in your post. Eventually they back off. Usually it's the dad but sometimes it's the mom. It all depends on which of the parents has the most influence and desire to alienate. It sounds like to your husband you are a uncomfortable reminder of a previous life and everyone around him has accepted his new life. 

We were friends with a couple, the man cheated and basically replaced his first wife with the second. They are very outgoing and social so everyone just accepted her though it was a bit awkward at first. His first wife kind of faded away. She is still a great person but less outgoing so her ex "won" the friends in the divorce because he tried harder to keep them. This happens a lot.

My husband has mostly given up on SD12 for the classic reasons. BM made it very difficult for him to have a relationship with her. He keeps hoping she will come around one day, I think she will when she wants money but I don't think they will ever be close. His sister gives him so much crap about giving up but to her she doesn't understand how you could stop fighting. Well after years of flushing money, time and emotions down the drain you almost have to give up. I told my husband that if I had been in his position I would have probably made similar decisions. 

You can take a step back, it's ok to focus on your own wellbeing for a while. No one says you can't start the fight again later. Your kids may soften up if the custody schedule is less of a battle. Try to go for quality rather than quantity. I know it hurts. 

A thought. How about you call XBFFs XH and the two of you create an alliance to return a wave of shit in the direction of XBFF and XH with their PASing manipulative shit.  XBFF's XH should be able to drag her ass to court to keep her from renamming his son, and on top of that you can go full facts mode on your  XH and tune your children to those facts.  Your 18yo needs a foot up her ass and you need to supply that foot.  She needs you to deliver her with absolute clarity regarding the full meal deal information on the divorce, daddy, etc, etc, etc...

When an X plays the PAS card, the response has to be total confrontation and full disclosure of information. Particularly with adult aged children.