If you want to be with him, I would see if he can live up to his word and not do it again, can work to regain your trust (by not being so friendly with girls on his own and introducing you to those he knows when you are together, etc.). I would set a boundary, tell him you don't want to hear any other rumors and you expect him to work out how to regain your trust. If he is mature enough to figure that out (I think most young guys think being sorry is the same thing, buying a gift to "make it up"), knows what emotional/relationship trust is and how he broke it and how to go about mending it, then there's hope for him.

But only you can decide if you want to be with him enough to take a chance on his not being mature or interested enough to be in relationship with you; you cannot "predict" that behavior I don't think, it is up to him to change or not.