Ex girlfreind visits to see our children but its making it hard for me to have a new relationship,advice?

I want to move on and find new girlfreind, however my ex gothic girlfreind visits to see our 3 children that live with me . we are still freinds and thats good for the kids but it puts off any new female freinds i meet. Tried dating sites but most people are as crazy as her but also phycotic. She just submitted a question about me (now deleted) from my profile regarding how she would like to punish me in a sexual way because she thinks i like it and will come running when she wants me to. Thing is that turns me on and i sometimes give in to her.so that also stops me from building a relation ship with someone. All i want is to settle down with a nice but occasional very naughty woman. Any ideas ? Please be kind (unless your a woman,lol)Ex girlfreind visits to see our children but its making it hard for me to have a new relationship,advice?
First, set some boundaries with her and with yourself. For you, stop looking at any of her online profiles. For her, if she's not talking about the kids, immediately shut her down. Don't let her talk to her inappropriately or like she's still your girlfriend. ';That topic is not open for discussion. Anything you need to know about the kids? No, ok, I'm hanging up now (or leaving).'; And do it.