Not Gay, But Willing to Try

I'm a 43-year-old man with a string of bad relationships behind him. I can't help but think that the one constant in all of these bad relationships has been me, but there's nothing wrong with me, so maybe it's the other constant: women. I wonder if maybe I am just not cut out for a straight relationship. Anyway, I know a gay guy at work, and he seems to be happy, so I thought maybe I could see what all the hubbub is about. Not that I think being gay is a choice or anything, I just am out of ideas, so maybe I could have like a trial run or something? Just to test the waters? Is that a thing?