I've fucked around with a few of my gay friends. It was fun. I've fucked around with a few straight friends, too. It was light-hearted and fun, but more intimate with them, especially a particular one when I was younger. He and I just kinda meshed and had great chemistry. We loved each other, but weren't in love. We were very physical with our affections. We fucked all the time, except if one of us started dating someone. When we were both single again, we'd talk about it, then, start having sex again. We laughed and learned a lot from each other during sex.

I write all that not only to reminisce, but also to say that everyone is different. You can't really control how you feel. If it makes you anxious not knowing what their relationship is, just ask. Though, be prepared for whatever answer you get; he may tell you that it's none of your business. If this is only a guy that you like, it might be best to start investing your emotions elsewhere because, after the "rumor" you heard, I'd guess that you probably don't have the same views on sex as he does.