Confronting a cheater?

I think the guy I've been sleeping with has a girlfriend. I wanted to confront him or at least ask him about. I thought about teasing him with sex and then asking him about it and threatening to leave if he doesn't tell me the truth. Now if they are supposed to be in an open relationship I would like to talk to the girl and ask her about it. If he says that they aren't would it be wrong of me to still ask to talk to her? And does this sound like a good idea? If so is there anything I could do differently?
Confronting a cheater?
4
1
Add Opinion