just found out boyfriend into men

Now here's the dilema i'm in, i've just found out my boyfriend is into cross dressing and txting other men sending photo's to each other! I'm very opened minded when it comes to sex but this kinda creeps me out a bit. We've not been together that long and have a great sex life but i don't know whether to confront him about it or not. Possibly it could just be fantasy and fun and he won't actually do it but the thought of him having sex with another man makes me feel very uncomfortable, my x had an affair and i feel sex should be just between two people any suggestions? I really love this guy and was hoping we were gonna spend the rest of our lives together but should i just dump him?