Wtf did I do

So I'm 25, been dating a guy now for about 4 months. Its serious and although you all are going to hate me in a minute, I'm definitely falling in love with him. But I did something bad today. I woke up from an hour nap to a message from a guy I was sleeping with right before my current bf. It was strictly just sex for months with the other guy. But I responded and went over there. I was already mad at myself in the way over, but I kept going.. WHY? WHY DID I NOT TURN AROUND.Anyway, we ended up having FANTASTIC sex. Was seriously intense but that was all it was. I feel horrible but I just needed it. That's sounds horrible, I know. My bf and I are very affectionte and we've had sex but he always keeps his shirt on. Always. I want some skin on skin. More intimate. He is in good shape and is sexy as hell. I tell him he's sexy and compliment him all the time.I 75℅ regret going to see my old hookup, and I feel selfish. But yet, a part of me feels happy. This is my dilemma. Why did I not turn around, even though I think I'm in love? Wtf.