I've been separated from my ex for nearly three years. He dumped me and started another family. He's very controlling and a bully. Everything seemed okay until I met someone else and now the situation has changed. The contact with our children has suddenly become very infrequent. He cancels literally minutes before I'm expecting him to pick the children up. I think I'm too soft and I need to take some control, but I feel intimidated and I don't know what to do.