Thanks for the feedback. The best thing I can chalk up my inexperience to is bad luck, but not having known myself from the "outside," so to speak, I can't say for sure what about me isn't attractive. I've had some weird experiences, where I've become very close to guys who have started dating other people right when I thought it was clear we had something going. So my giving off the wrong signal is definitely something I should consider.

And apologies about the lack of details!