C.W.
I think you need to do your best to keep your kids involved with their father. Encourage them to be together more and promote their relationship (unless you left out that he is a crazy child molester killer). Children need both parents even when divorced. I was unfortunately divorced when my daughter was four, she's almost eighteen. I live ONE mile away from my ex to maintain and foster that very important relationship. Yes, it's a lot of work being a divorced mom without family for help, I am in the same situation but access to both parents is more important.