What is wrong with ME??

Birthdays can be fun. They can also be horrible on occasion. Sometimes, just when you think everything is going well, it takes a sharp turn for the worst. That was kinda how my birthday was. The day went by pretty well, and I invited a special friend to go out with me to the bar and hang out shoot some pool and with intentions of hopefully fulfilling some desires that both of us had. He called me and said he would go but couldn't stay out long because he had an event he had to go to in the morning, but definitely wanted to go out. I went and picked him up and we went down to the bar.
We kept exchanging seductively, flirty suggestions through out the night and I thought that everything was going good. A few acquaintances joined us while playing pool and I started noticing that his attention had focused to the other guy. Then the not so subtle flirting. At the end of the night, he hopped in their cab leaving me alone stating "I'm going with them."

At this point, I have a good idea of what POSSIBLY happened. I don't want to know if any of it actually happened or not, I really don't. I don't care. I just want to know what is wrong with ME??? Why is it that someone is interested, then another guy comes along and suddenly I'm no longer what they want, it's the other person. What's wrong with ME??? I'm a decent guy, I have my faults, my quirks....but when establishing a possible fuck buddy or one time fling doesn't happen even though they've been "wanting to fuck me for quite some time" and turns into "oh, I'm going home with someone else" .....It leaves me wondering what really is so wrong with me? Maybe he thinks that because he's able to get a hold of me easier, it's ok to ditch me for someone he may not see again. I don't know.
The whole situation and everything that happened has been replaying over and over in my head and I can't quite figure out what exactly am I doing wrong. I try for a relationship....that doesn't seem to work because of complications of either, distance, preferred position (top, bottom, etc.), or the classic "found someone better".
I'm confused and a little hurt, forget the fact that it was my birthday. Yay, I got dissed and dismissed on my birthday. .......I feel like the more I try, the less I try, it makes no difference. I actually feel bad for the guys who get to know me and end up falling for me when it's not mutual. I really, really, do. I know how it feels. It can be confusing, frustrating, and depressing. Yes, I've been there on many occasion. I always try to at least give the person a chance, see if there might be a connection, however, that tends to end up seeming like I'm being misleading.

I'm at a loss, I'm not sure how to feel or how to react. Part of me is frustrated and upset about what happened, but there is also the other part of me that thinks that there isn't really anything to get too upset about, I'm over thinking things, and that there is ample time and opportunity for us to follow through with what we were planning. In the mean time, I'm not gonna make any rash decisions and/or actions. Let it flow for now. But still, there is always the lingering question....What's wrong with ME? Why am I always the one trying to win and keep another's attention. How come I'm not good enough?