I'm not really sure why you're so conflicted. I'm bi, so maybe the whole concept of being strictly and absolutely sexually assigned to just one gender escapes me. Maybe you should try having sex with another man, someone you find attractive. To see if you possibly be bisexual. You're an extremely good looking dude, with a pretty damned nice cock; you should have no problems meeting someone to your liking. I'm sure you've been hit on by guys, maybe you should put aside all the preconceived notions you've been carrying around in your head and expand your sexual horizons. You set the limits as to what you would feel comfortable doing with another guy and just relax and give it a shot. I'd suggest you try it at least three or four times, with at least two different partners, just to get a real barometer of your personal situation. Don't be embarrassed, bro, sexuality is not a black and white issue. But I do agree with Pendlum, there are just as many relationship issues in gay relationships as there are in hetero relationships.
Not everything is greener on the other side of the fence.
But you seem like an intelligent guy, experimentation will not hurt you if you approach it safely and sanely.
I wish you the best.