I think a lot of us ask ourselves this very same question. I too have been attracted to both but have always dated men. I don't know if I date men because its easier or if thats just the way it has worked out. I think that if I had met a woman who I was falling in love with, I would have tried it.
In all my past relationships, I'd always wonder "is there anyone else out there?" Now I'm finally in a relationship with a man where that question ceases to come up. I feel in love with who he is....now if he had been a woman, I probably would have fallen in love with that woman.
I've said for years that I wouldn't limit myself to a specific gender, but I never labeled myself as bi or anything....I don't know how to describe it. It wasn't necessarily out of frustration with men (though there were countless times when I said I was gonna try the other team haha). I think for me, I was always able to see things in anyone, male or female, that attracted me, and I wasn't willing to limit myself.
Yes, I agree that a same-sex relationship would be more difficult then a hetero one....I think that love would overpower that for me, but I wouldn't know, because I never did it.
I guess the saying "to thine own self be true" comes to mind. Do what feels right for you, not what feels right by others.
Good topic btw.