I feel you man, the same kind of thing happened to me some time back...
If you do a research on my old topics...
Some people are just plain selfish, they don't mind stringing people along, guess that's just life.
That should be a lesson... don't waste your time pursuing a girl when she turns you down the first time you ask her out. NEXT her right away.
But don't go extreme because of this unfirtunate "incident" though...
Just be more "wary" next time.
In my personal case, this kind of thing made me more "laid back" and less "enthusiast" right away now. Even if a girl shows big interest immediately, I still "wait" to see if it's really genuine and there's no hidden complications such as a boyfriend or something like this.
Most of the time, the girl DOES like you, but she's happier having the boyfriend AND YOUR ATTENTION.
Four of my personal experiences:
1) We know each other for a couple of months, we see each other on and off, but purely on a semi-official context: a language club. Over the time, something developped and I was thinking about going for more. She seemed ok with it but some times would be "busy". (I don't assume automatically that people are liars, they always have ONE chance). When I find out through a mutual friend (actually more her friend than mine) that she has a boyfriend, I was pissed. Didn't cut all contact, but it became pretty cold...
2) Some girl I met through the musical I was doing. Britney Spears wanna be type. Showing too "early" all the signs of interest, turned out to be a fraud, actuallyhas a boyfriend and her boyfriend started to ignore her for some reason so she was probably looking for compensation. Same as the first one, relationship became cold after I found out.
3) A girl I liked who also liked me. Sometimes seems interested, sometimes totally not. Looks like she was undecided. Never lied to me about a long distance boyfriend, but never mentioned it either, I learned through other people.
Because of previous experience, I said to myself "no no". Eventually she broke up with the nerdy boyfriend but our relationship is so complicated and looked more like a friendship that I didn't even bother.
4) A real gorgeous and kind of shy girl who came talk to me on the bus for a school event. Had a boyfriend who looked kinda like a abusive thuggish dude. This one was genuine. She sure wanted to drop the boyfriend. But due to social circumstances that would be too long to explain here, I couldn't get to interact with her except a few very brief exchanges in the school dining hall.
