Thank you everyone for your input. I'll do my best to address the questions brought up.
We were married after we opened the relationship, about 6 months. Opening the relationship was actually my idea. I had had open relationships before and enjoyed them. When we first got together, he was not amenable to the idea but as our relationship grew stronger, plus the fact that several of our friends are in open relationships that work and he was able to see that, he became more open to it. We started slow, with just loosening boundaries and then became fully open a little over a year ago.
His girlfriend is a mutual friend that was actually originally trying to hook up with me, but I wasn't interested. They started hooking up around the time that we were loosening boundaries and then took it further when we opened. He is not the type to sleep around casually so I always understood that there would be a level of caring since they were friends beforehand and also, they both lost a parent within a month of each other so they were able to support each other in that in a way that I couldn't; but when we first started it was both of our understanding that our marriage was our main relationship and anything else was secondary.
I understand what you are saying, GalaGirl, about the original agreement being bad. I realized that after our big blowout about their feelings for each other and part of the reason that I let it go was because I did realize that it was unrealistic. I do believe that love is not finite and that if he loves her it doesn't necessarily mean he loves me less. So after that fight, we all understood that there would be an emotional connection between them and I was truly ok with that. There is, however, a difference between loving both of us and wishing he was married to her instead.
To add another layer to this, this has made me really question my feelings for him as well. I have been asking myself if I'm still in love with him and so far I don't have an answer for that. I am not good with picking apart and identifying my emotions though and I am still kind of in shock about all of this, so I know I'm going to need some time to fully understand how I feel about that. I have also built a pretty strong connection to the guy that I'm seeing so that makes me very hesitant about insisting that they break up or closing the relationship since I don't want to discontinue seeing my dude.
It's still pretty confusing. He acts like nothing has changed and in fact has been reaching out to me more in the last few days. He's in a great mood today, although the pessimistic side of me thinks that's probably because she's coming up for a visit today. It's very tempting to just pretend I never saw that message and just continue along in the relationship. I know that what other people think isn't important and normally I don't care, but the thought of breaking up or divorcing after only having been married 8 months is humiliating. And we were SO SMUG about how we had everything figured out and how our communication was so great and how we were doing this open relationship thing the right way. Ugh. I guess that should have been my first clue that something wasn't right haha
I know I need to talk to him about all of this, but I am dreading it. Plus, with Christmas around the corner, I don't know if I want to blow all this up right now. I'm just really unsure about a lot of things right now.