What should I do about this siduation?

Ok so there’s this guy I was engaged to… also (highschool sweetheart). We were sooo close and everything. We have known each other for 5 years. He’s in the Navy which means we were away from each other a lot. He started cheating and we broke up or whatever. The girl he cheated with he married because she got pregnant anyway he textes me all the time and calls me telling me he’s not happy with her because they get into it more than often and he misses me. He be flirting wit me on the phone and everything. I still have so much love for him but I really don’t know what to do about this siduation. I’m not the type to take a cheater back though, it’s just the feelings are getting in the way. If you ask me, I think he had it coming though… you don’t just up and marry anyone you’ve known only for a few months. He even told me that if we were to mess around with each other it just happens and it’ll just mean him and his wife was not meant for each other. I don’t know what to think but anyone on here wit any advice let me hear it please.