I was where you are now in 2013!!!!!!!! Plus my xh married the OW, they had a nice house, money and were also pushing hard for her kids and mine to all move into this big beautiful house they bought. I was terrified my SA xh and the OW (who was involved in a murder/suicide and SA) would get my kids from me.
So, with advise from SI and from friends this is what I did: (and it has worked out very well in the long run).
Note: if he were not manipulating my kids, I prob would have been more negotiable on things, but the few times I gave in, he told his family and friends I was pawning them off on him, when the opposite was true).
I was very fortunate that 2 of our family friends have good husbands who would take my kids to do guy stuff.
If your kids are in athletics, band, any activities please keep them in it to have good role models.
So, I stood up for myself and did not give up any of my visitation. (Xh always planned vacations, fun things to do on my time.) I would email him and attach a copy of the visitation agreement he signed. I had first right of refusal, he left kids with OW, I called him at work and made him bring them to me. He wouldn’t return the kids one weekend, I called the police, they met me elsewhere and we went to get them. I NEVER got on the phone and argued with him. I kept it very professional and in writing. I told my kids our property lines were our safe space. When xh and ow showed up here raising hell in the driveway, I silently walked away and called the police. My D papers say no fighting in front of kids or where they can hear.
ff a year: ow kids moved out from her back to their Dads bc of all the fighting.
Then, xh began canceling on our children & I always happily got them. (Please try to put $ aside so that you can do something fun with them when he backs down.) ex:my xh canceled his Christmas visitation with them. I called a friend in Florida and we drove straight there. (Some people on SI say to not get the kids when the xws backs out, make him responsible, so if that happens to your kids, you could post here and get a different input).
One son wanted to live with his Dad at one point bc his Dad had promised him a car. I told him to really think about it, that the judge had assigned his residence to me. (I was inside freaking out). I had him think about it, and about that time xh began drinking heavily and he didn’t bring it back up again.
Eventually xh stopped coming to anything of the kids, and that was truly heartbreaking. But it’s who my xh is:only there if it benefits him.
Once my kids could drive, they would go and come back on their own, and leave when the drinking and fighting started at their Dads. Dad would put them down and I told them they don’t have to go anywhere that they are degraded, even if it’s a family member.
Now they rarely go to their Dads-now 24 and 21.
Btw-they both grad college and have jobs. I think they are very good hearted people.
And all this time I actually never bad mouthed their Dad to them (but I vented on SI a lot !!!!!).