Sorry to hear you are having a rough time. I've been in the same type of situation. Hope it gets better for you.

I'm going through a similar time and its not easy. Especially with the kids. Its really difficult not having them with me (I have them most of the time). You can do it though, I work really hard at not arguing in front of the kids but in the end we will both be there parents so at a minimum we need to tolerate each other.

Move forward. Don't say a bad word about their father or the woman of the hour. Years from now you will be respected. Children learn what they love. Lead by example. You will be ok. They will be ok.

Parenting is a huge responsibility. Try and get done with the bitterness to make it feel like a pleasant one.
My best wishes!