Gay-Straight friendship

[Gingerguy]

I have a friend who is 45yo (I'm 30). We know each other for 6-7 years but we came way closer after the loss of a friend of mine. He is the guy that would make me nervous. Loves to be in suit, he's a surgeon and professor, he knows so many things. He helped me throughout my sexuality by giving me advice which is rare for a straight guy. Technically he's married, although his wife is a university professor in the USA (so they're an ocean apart, it's almost poetic). I really don't think he cares. Neither for her, nor for anyone else. I know he has fucked around occasionally however he doesn't seem to feel horny that often. He needs affection though. We spent quite some time together. I love him as a friend, but can't help but wonder. Why is he not with his wife or with someone else? All my senses tell me that love is what he craves. I don't really think he is into me, but on the other hand he loves me too much. I don't wanna sound without confidence, but I don't know why it's me. From my experience, other guys don't really matters to str8 guys. Moreover, that guy makes me feel that he had too much of bad experiences and he doesn't trust people. But he seems to trust me. Once, after a bad day for all of us he had cried and asked me to never leave him alone. If he was gay he had many opportunities to approach me. So I think that him being gay is not a possible scenario. But I don't know why all these.