So this guy and I had a thing for eachother a few years ago, but it didn't work out and in the last year, he's gotten a gf who happens to be my mortal enemy (she hates me, but i simply don't care enough about her). Very recently, he's been snapchatting me more and we're talking again and I can still feel that he has an interest for me. However, I don't think he'd leave his gf but is it wrong of me to reciprocate conversation, if i feel that he is still a bit keen for me deep inside but has a gf? What should I do?