My BiPOLAR Significant OTHER has left me after 3.5 years together

HI,

I can't explain how hurt I am. My girlfriend left me after she decided that she just was not attracted to me anymore and that she didn't even enjoy kissing me. She says she does not know if she was just "experimenting" (it was a gay relationship) but that even though she loves me and hates the fact that she doesn't feel the same way anymore, that she wants to be "friends." It's important to say she was hospitalized last summer for a severe depressive episode. Since then, things really started to changed. I was there for her during this whole time. In good times and bad. Now she wants to keep me close (as a friend). It's also important to say that she did have some "internet affairs" with MEN that she was flirting with online. Close friends of hers told me she never actually met these guys but these e-mails were charged sexually. She said she needed to figure out her sexuality.

Anyway, after 3.5 years I feel like a complete idiot. Like a doormat. I thought if you were a responsible, loyal, and compassionate lover that things would end differently. This wasn't what I expected after everything that we've been through together. She says perhaps the "excitement" of her experimenting phase died out....but that she still LOVES me as a person....but doesn't want to spend the rest of her life with me.

I'm torn and hurt....angry and have become depressed myself after this painful relationship. She wants to be friends but I'm not sure I can put myself throug that because I feel it will be harder to have a "friend" that was once your partner and lover. Suggestions?