Another Join In The Club

I knew that one of the people I used to frequent is gay.
Whoa, how weird this is!
Suddenly a lot of things come up to my mind and just now I understand some of his reactions I had judged strange, unintelligible or at least pretty original.
For example his insistence on sentencing that my long term friendship with a common mate of ours *had to* be definitely over, with no chance of recovery. Instead of trying to be kinda supportive of me, he had very harsh words...
But this makes me wonder if our sexual identity can be influenced someway... I still think that if a *real* straight guy lived his whole life in a gay bar he would still be attracted to women... however this was nearly shocking!
I'm living a nice friendship with a guy but I can't figure out what kind of person he is actually... his temper merges a good guy's sensitivity with an ordinary lusty behavior...