What she is doing is totally not cool, and I'm surprised that she's getting so much support. If you have "friends" who are not talking to you, then those aren't friends. Friends will talk to you, even when they think you are wrong. And no one outside the relationship is really in a position to judge.

It sounds like you brought more commitment to this relationship than she did. Couples have to resolve problems between themselves, not by conducting a referendum among their friends. Caring friends will be the first to remind a couple of this. These acquaintances of yours sound like they just want to be part of some drama.

Maybe the best thing you can do is nothing. For those who still are speaking with you, you could express that you are saddened to be going through a falling out with someone you care deeply about and wish you could resolve the issue with her. But don't get real defensive and bad-mouth her. Take the high ground, and don't feed in to the scuttlebutt. It'll die down sooner that way. Cultivate the few most loyal friends you can find, and disregard the rest for now.

This whole unhappy situation may be a sign that this relationship is not meant to be.