I know the situation sucks, but talking with your wife is a good thing. Although it may be hard to know that she can't accept poly, you can talk to her about the difficulties you have. By keeping open communication going, she can start to trust you more since you couldn't be cheating if you tell her everything. You will feel frustrated at not being able to have a relationship with another woman sometimes, but at least you can share your feelings and work through them with your wife. Who knows maybe she'll one day change her mind, but a high pressure approach is just going to get you the divorce you don't want.
If you do stick with her, I'd suggest reassuring her that your decision is to stick with her and you won't pursue other women. I'd also suggest doing everything you can to be romantic and affectionate since she's probably feeling pretty vulnerable. Maybe try being more open about other things as well. If you discuss everything with your wife, good and bad, she won't view conversations about poly as a "You have to do this or else" conversation and more as a "I'm hurting now, please understand" conversation.