100% agree with Blu ... It's kinda what I've been saying all along. Cherry, I hope you're ready to really hear this advice and use it.
I'm telling you I acted like you and was walked all over by my H. He had left me and was treating me terribly yet I was still available to him. Once my tune changed so did his.
Sure your H might not change but what's it going to hurt? He's already filed, moving and is done so in my eyes you've got nothing to lose. Yes you want to be amicable for the children but that can't be one sided so worry about that when he's ready to do the work to be cordial for the purposes of the children.
I told you a long time ago it's time to tell him to leave. You won't tolerate living with someone who is actively pursuing another woman whether he wants to admit it or not. I believe I used the line to my husband when he denied it of something like please do not insult my intelligence with your blatant lies and slammed the car door shut and left. He got the picture.
He needs to respect you but you have to require him to do so. Asking him if he wants dinner is not something that's demanding respect. Oh hey H I know you're messing around, not spending time with s and plan on divorcing me but I made dinner do you want to join us. Would you let a friend or a stranger treat your is way? If the answer is no, then why let your H treat you like that?
My grandma always said the behavior you accept is the treatment you deserve. While harsh it has some truth to it.
