kdt26417 and Boring Guy, I'm glad that there are people who see it that way. I had been nervous about saying anything about it because when I first came on this forum a while ago, there was a thread from a woman who felt threatened by her husbands secondary relationship and wanted to veto it. Most of the comments were extremely negative, with a lot of "you're not really poly if you don't let your husband have this relationship" and "suck it up, you let him do it so now you have to live with it forever" kind of attitudes. I know not everyone is like that, but it did make me nervous.
Honestly, I think I know why he feels this way. When he's with her, it's like vacation romance. They don't have any responsibilities, it's just hanging out and sex all the time. Also, she is crazy attracted to him and all over him all the time, which I'm sure feeds his ego and makes him feel good. While, with me, it's real life and paying bills and stressing about money and cleaning the house, etc. Also, while I love him more than anything and our sex life has always been pretty good, neither of us has been "on fire" for the other in quite a while. And that's fine with me. It's part of the reason that we opened the relationship, so that we could have other sexual experiences and still have our steady and strong relationship. Now though, apparently, that makes her more attractive as a partner.
That said, I do understand that it is going to be painful either way. I'm also worried that if I do veto his relationship, he will want to make me stop seeing the guy I've been dating (who I like a lot and care for) or will want to close the relationship. I suppose if that were the only way to save my marriage, I could do it. Hell, we were monogamous for 5 years successfully so it's not like it can't be done - it's just not as much fun.