If what she wants is a monogamous life with you, which it sounds like may be the case, then she's going to have to bite the bullet and leave this other guy. I hate to say that as it's not really "fair" to him but it sounds like it might be more true to where the two of you are at. Leaving someone is never easy or fun, but she may just need to be strong.
On the other hand, if her feelings for this guy are strong enough to outweigh both her discomfort and yours at this situation, maybe you should go beyond meeting him and try to befriend him. If the three of you can do things together socially sometimes, you won't have to miss her as often, and maybe your jealousy would be less towards someone you have positive feelings for in your own right.
As for the issue of her not wanting you to be with other women, well, it doesn't sound like you want that either, so no biggie. Now if she tried to make it a rule that you couldn't be with other women, while she had another man, that wouldn't be so cool...
The major players. Me, 30ish bi female. Gia, girlfriend of 4+ years. Clay, boyfriend/dom. Davis, ex/friend/"it's complicated." Eddie, roommate & fwb.
The supporting cast. Eric, Gia's husband. Bee, Gia and Eric's toddler. Dexter, Gia's lover. Helen, Eric's lover. Izzy and Nikki, Clay's partners. Liam, Eddie's husband.
Last edited by AnnabelMore; 09-19-2011 at 05:35 AM.