Yeah, I've been through it before so I know the ropes on how the whole parental alienation thing can work.
I know ways to combat is and I always have very open communication with my kids so they know. My daughter asked once "Daddy, why did you always yell at mommy all the time when you were together?" She was only 2 when we broke up so she doesn't remember us even being together, she's 9 now, almost 10.
Before I could even speak up my son said "He didn't, he only yelled when he was being yelled at, and if mom hadn't cheated maybe there would have been less yelling"
He was 11 when he said that, I'll never forget it. I've never even talked to them about it, so he remembers on his own. I've never said anything negative about their mother and when my current wife would, I would always stop her, the kids don't need to hear that. I know in time things will straiten out, just gotta get there.