It may happen that you could be attracted to one more than the other, just try to share your time and passion equally with the other two guys.
Agree. This can happen a lot. Be aware of it, and don't expect it to work out the way you expect every time. Although, I was with a couple once where it was basically me with one guy while his partner watched, and they seemed to enjoy that, so... whatever works.
As marky said, just relax and enjoy it, and see what happens.