Advice needed from friends

Ok, here's the deal... I need some advice... (sorry guys if this seems to be along the lines of guy bashing...)

I have this "friend" in Tulsa that I went to college with... he is really sweet, nice, kind, caring, blah blah blah... we became reacquanted when we started graduate school... we started talking, then enters Trevor... we still talked since Trevor and I were not an item... after Trevor moves, this "friend" and I decide that we might date... then he starts dating his ex, again... well Trevor and I become an item after a while.

So this "friend" and I have stayed really good friends throughout our graduate school career. We talked on the computer, texted back and forth, emailed... talked when we could, hung out. I should mention at this point, that this "friend" and I always flirted, innocently knowing that nothing would come of it since I was in Texas. This summer, this "friend" and I actually had a chance to sit down and talk about what we thought about everything. We both agreed that we liked each other and that it was a shame that we never got a chance to see if things would go anywhere, he knew what was going on between me and Trevor, and I knew where he stood with his issues about his ex.

One would think that since Trevor and I "broke" up that this guy would be interested in talking to me... but instead he has avoided me... I don't understand! WHY is it that guys do this to us girls? Flirt like crazy when we are in a relationship, tell us that they like us, then when we are single, they start dating someone else????

The funniest part of this whole scenario is that I knew that he was dating someone by the way that he was treating me, yet he wouldn't admit it to me! That is until the other night when he actually replied to one of my messages... My problem is that although I still care about Trevor and would like for us to get back together, I have always wondered what would have happened if this "friend" and I dated. I thought that I might have that chance to date this guy and figure out that mystery once and for all, but apparently he has some other intentions in mind. I hate how guys say that we play mind games, when their mind games hurt so much more and are more frequent.