My ex wife

Why doe's my exwife do this to me she  dosn't want me and I have finaly am good with that ,  but as soon as I find somebody she start to get jeosuy,  she dosn't want and she dosn't want me to be happy.  I'm trying to be nice becasue of the kids but I think the only way I can be happy and not let her blow up any relationship I have is to be a asswhole.  I can't be nice to her anymore becasue I end up doing to much for her.