Divorce and the children

I have been separated for a little over a year and I am about to file for divorce. Along with this I have to file an order for property distribution. I am at the end of my rope here because by soon to be ex has made my life miserable over this period of time. I currently have a 50-B on him but I believe he still comes and sits outside my house in the middle of the night when the kids are with him for the weekend. I left him because of his continuous infidelity. He has put in alot of time trying to assassinate my character, telling everyone we know that I left him because I was seeing someone, didn’t want to be married or things like that. He is currently seeing our 3 kids every other weekend. Since he figures I am getting ready to make a move he has went into overtime spreading just plain lies about me, what I am doing, etc. Through all of this he is seeing someone and she has even sat outside my house at times (I don’t have proof), has left rude messages on my phone to where I got my number changed. The thing that is tearing me up at the moment is that he uses our children and will involve them in this mess. When they go over there he has conversations with them that he should not have, talks about intimate things that went on before we moved out. He refuses to really do anything for them. Since I put him up for child support he feels that is all that he needs to do. He threatens that they can’t come over to try to get back at me. Meanwhile my children are suffering and I am trying to do all I can to be there for them. What I am thinking about doing is stopping their visits with him based on the drilling and everything they go through when they are with him. He is going to say that I am trying to get back at him or whatever but I don’t want them to have to go through that. I don’t know if he could use this against me in court when we go or what. I know I also need to get them someone to talk to and I am working on that. I thought that he would at least do right by them if not by me but I see that is not going to happen. I feel so bad about all of this. He has always been very controlling in our marriage and always gotten what he wanted. Since I won’t come back to him like he thinks I should he is trying to destroy me. And my children are going to be casualties of all of this and I don’t want that. I know I have been rambling on. This has really been eating me up and I didn’t have anywhere else to go and vent. Thanks to all that have taken the time to read this.