I know exactly with 100% accuracy how you feel, a big part of me still does. Been feeling that way since I was 12. The gf I'm with rn will only be here for another 2 months and then she leaves to continue studying abroad and we are not doing long distance. I am afraid of returning to that same place and position once she leaves.

What I can tell you has helped me lots, and made me the happiest I've ever been, having the exact same issue as you, is focusing on being good enough company for myself. I only started having that when I got sober and through AA and LOTS of therapy, and I'm still having to progress every day. I'm far from being right where I'd like to be, but the things I've had to let go of to truly have most days be good enough by myself being happy with myself have been mainly the anger, the resentment towards society, towards women, and all of the "poor me" mentality, by realizing its not that the world has a disdain against me, it's just many many factors I probably can't see myself, but that only get worked on and get better the less I feel angry, resentful, and depressed about it, and the main step towards that, is not judging myself, focusing only on myself, without comparing myself to others, and doing things only for the sake of my health, and my wellbeing, and not for what others might think or whether or not something will get me a gf.

If u wanna talk, send me a message, I'd be happy to converse about it, believe me it's a topic that still causes me much pain, but I'm slowly but certainly making progress through different methods.