why is this a constant in my relationship life?

Ok so for some reason there seems to be a constant and not so much in a positive way. I've been wanting a good relationship for as long as I can remember. It seems like I start talking to someone, they seem interested then things just fizzle out and that's that. Also it seems like later down the line of these people after being flaky or just lying to me say hi and make small convo when they see me and I almost take offense to that thinking "if you were so fake to me why the hell would I want to talk to you now?". On top of that if someone is interested in me it's like they say they like me, we may go out a few times, have sex a few times then they're on to the next dude. So over the course of years of this b/s I seem to have grown bitter & jaded nowdays. I may come off as passive agressive at times and maybe it's from being burned so many times that I don't know how else to express how i feel anymore. I have a lot of hobbies, work hard, well travelled but I feel like either something is wrong with me or I was born in the wrong era. I have some ladies tell me how nice and sweet they think I and im like damn if that's the case why the hell am I always single then? I'd like to get out of this funk but I'm not sure what to do anymore I just continue to feel jaded every time something fails. Any advice?