[hutzlibu]

If you are only into sex, I guess it will be way easier to just pay for it, or go to places (online or offline) where casual sex is common. Otherwise friendship is about way more for most people. And if you cannot stand the ordinary (awkward) socialising, which I can relate to, I recommend finding a group that is more to your liking. Then socialising might be fun.. Usually when it is not about socialising, but the activities.

[SoftTalker]

I didn't read it as only being in a relationship for sex, but that it's a motivator for socialization if you don't have it. Once you have a relationship and a sexual partner, there's not much motivation for additional friendships/casual socialization, if you're an introvert.

[globular-toast]

Oh, no, I can't do casual sex. I require a monogamous relationship. I get much more out of my relationship than just sex (like love, for a start) but the sex has to be there. It doesn't make sense, but that's just the way it is.

[hutzlibu]

"It doesn't make sense, but that's just the way it is."

It makes sense in a way and you are the way you are .. but I think you might benefit from trying to open yourself to new experiences, unless you want to repeat the cycle again and again. (Oh and I don't mean casual sex. Rather something like interacting with people in a way you have not before, which is easiest by going somewhere you have not been before.)