Would you be any more bitter if she dumped you for another woman?
That's a good question. Being dumped always sucks. If she left me for a woman, I'd probably feel jealousy and resentment... "what has she got that I haven't got" etc. If she dumped me to go back to a heterosexual relationship, I think I'd feel a sense that I'd been used... that it was "just a phase" for her, or that she was just curious or experimenting or that sort of thing, that it was never real for her, that I'd been lied to. They'd both suck, I don't know which would hurt more.
While the sex might be different, is the emotional relationship any different between a straight and gay relationship? If she has had both, it might make an interesting conversation.
For me, when I was with a man who I really cared for, he was 12 years older than me and he had this guardian, mentor, protector aura that I found really attractive. He was a rock, an anchor, a fortress, (insert other cliches here), a calm and reassuring presence in what was otherwise a pretty confusing time for me. I really did love him, and spent a long time trying to convince myself that I was heterosexual as a result.
I've never felt that same sort of dynamic with women I've been involved with. Or other men I've dated either, for that matter. I don't know how much of it was to do with him being a man, how much was to do with him being older and more emotionally secure, and how much was just his personality. Some men have qualities that deeply appeal to me, emotionally, that I haven't found in female relationships. Trying to make generalizations like "men be like this, and women be like that" never works, but I've never met a woman who had that guardian spirit that I felt with my long-time male companion.
-k