Nearly everybody is somewhat bisexual, with only about 10% each being completely hetero or completely homosexual. The fact that most of us don't think of ourselves that way is largely a function of programming and opportunity. I thought I was hetero until about age 50 because I knew I wasn't gay. It turns out that I'm really pansexual.
You may indeed be one of those guys that is in the 10% truly hetero, but I'm also going to bet that a lot of what you are feeling is a lifetime of programming. My husband just started kissing and playing a little bit with a guy and although he had to get pretty tipsy to do it the first time, he really enjoyed it and is very comfortable with it now. Even though my guy really wanted to do it, he still had to grapple with a lot of programming right up to the first touch, and the first kiss. I love watching him with our play-friend. It doesn't look "gay" (whatever that means?). It looks like two human beings connecting physically. I love to stand between the two of them and have them kiss me and then kiss each other over my shoulder.
And all of that being said, you should definitely do or not do what feels right to you.