I feel you, i have the same problem with my girl. She wants to be able to **** other girls........ without me.

kill it with fire

What's the point of getting married if both of you don't want to remain exclusive? Depending on where you live, there might be financial incentives, but really? At least she's raised the issue prior to the big day, OP. But I'd be having some very serious talks with her and asking her why she would bother making a commitment she has no intention of keeping. Good luck!

Pretty sure she's already cheating... I'd kick her out or move out now

Go with your gut, you obviously are not happy about it if you're posting it on fml. Also the bigger issues is kids, how will you feel if she gets pregnant by someone else, you will have to dna teat when its born or live with the thoughts and doubt that it might not be yours, is that something you arw willing to do??

Bang her sister, then watch the attitude change.

hey sorry to hear your having such a bad time with this dude. I'm actually in the same situation... but on the other side. I've been with my boyfriend for a year and I brought up that I'd like to have sex with other people just a few days ago. He kinda knew about me being poly before, but I've never done anything behind his back. We're getting so serious now and its been so long. I'm just saying, i see it from her perspective. are you sure you can't budge?

An ex told me the exact same thing, once. I made her realize how stupid she was sounding. Try the same, dude. Maybe you can talk some sense into her...

Thats a keeper !

Yeah...I'd tell her "well, I do, so you've got a decision to make here."