Why can't I catch feelings? need help?

For some reason, I never seem to like any guy I meet for that long. It's like emotional connection and intimacy are 2 separate things to me. I can have sex without attachment and as bad as it sounds, I kinda prefer just being intimate with someone and not seeing them again afterwards.
Each time i've gotten close to a guy, it's never lasted longer then a month. Any longer and I just start disliking the person a little TBH. I know it's wrong and ofc I make sure not to hurt anyone. I don't get involved with a guy I know has actual feelings for me cuz i wouldn't want to hurt him. But I just don't understand...
I've never had a boyfriend. My mentality is strictly "all good things come to an end". I know nothing is going to last. Back when I was like 13 I had an intense crush on a guy, and it lasted until i was like 17... which i know is sad, but that's as much as I've ever liked anyone. I also really liked this guy last year, I felt somewhat of a connection with him but he turned out to be an ass so it never worked out.
They were the only 2 guys i felt something for, every other guy I meet or get with just can't seem to get to me on a deeper level. I start talking to them with the comfort of a friend, and eventually they initiate physical contact and that's about all I seem to want from them until they leave.
ALSO I'm ALWAYS very awkward when it comes to the first physical encounter, I ruin the moment by laughing or making some joke idek...
Why can't I catch feelings? need help?
Add Opinion