Your sexual orientation can shift around on The Kinsey scale, this is most common when your young, although I guess it can happen at any age.
I identify as straight, I do not look at men now, and find them sexually attractive at all. The idea of having sex with a guy does not repulse me, but it doesn't turn me on either. There was a time though (14/15) when I was confused about my sexuality, and pretty much convinced myself that I must be gay. This was because the first real emotional/sexual relationship I had, was with another boy at my school. I think there were lots of reasons why this relationship happened.
1. He was two years older then me, and he was someone I thought was really cool, I really looked up to him.
2. I went to an all boys school, so no girls around. haha
3. Hormones, I had got to the stage were I was tugging it to the weather channel,
so I was bound to respond to sexual stimulation.
We would go back to his place after school and make out, it was more than just sex though, we really liked each other. This relationship lasted about a year, until he went away to Uni, and we were both sad about it ending. I have no regrets about it though, in fact, we both look back on it very fondly. We bump into each other from time to time, and he still teases me about it, and unlike me, he does identify as gay. At the time I did really enjoy making out with him, in fact I was more comfortable in my role with him (I was the Bottom) then I was when I started with girls.
I guess he was the right person at the time, because I have never been attracted to another guy since.
Like others have said, just because you like pegging, it doesn't mean your gay/bi. My girl is into BDSM, which I'm not. She figured that although I would be no use to her as a dom, maybe I could sub for her, and she did mention pegging as part of that. I'm not interested in it though, as it does not turm me on, either to be dominated or pegged. If you enjoy it though...........Go for it.
Only you really truly know if you want to have sex with another guy, if your not sexually attracted to them in anyway, I cant see it working. The thought of it must turn you on though, or you wouldn't be thinking about it. The only real way to find out is to give it a go, and see if you like it.