Anyway they ever change? and resentment

Two part post:

First: My ex DH doesn't call my girls ever. He's seen them a handful of times since I had him leave in Feb. He shows zero interests in their life, doesn't want to see them, doesn't visit, call, or anything. Anyone ever had an ex do this? When I told him to leave in Feb. he didn't protest. Didn't try and stay, nothing. I told him I hadn't loved him in a long time. I was staying because I was secure in our situation. He told me he doesn't resent me or isn't mad. He was trying to re-enlist in the army (they wont take him back) he has a gf currently and she has no idea he has children. Do they ever change?

Second part: my oldest who is 6 (will be 7 in Jan) HATES her dad. Wants nothing to do with him. She is quite fond of my bf, and granted he pays more attention to her than her dad ever did, I don't really want her hating him.

They don't ever change, and the fact is why should they get the chance to. Whether your kids like him or not, he is their dad and his attitude is hurting your kids. If she likes your bf, then nurture that bond if you think he is someone that you are going to stay with. The more your kids see you putting effort into your ex and making him be a part of their lives, the more they will feel bad about it and feel like it has something to do with them. The only thing that you have control over is taking care of your kids and yourself, and I think if he hasn't put forth any effort, then his opportunity has come and gone. Good riddance.