I think I originally said this: "Before I will even consider having this discussion, I need to know from you that you have ended the relationship with her, completely, utterly, and permanently, and I need you to know that any further contact with her will immediately result in any sort of relationship between us ending permanently."
Why keep beating around the bush? In my view, you are giving him ammunition by not calling him on it.
If he lies, then you don't even have to think about it anymore.
