You don't come out as poly like you're gay. It's a lifestyle choice, almost like being a nudist. Many people are attracted to other people outside of their marriage, its normal, but that's why it's called commitment. I could leave my husband right now and start something with someone else, but in our committed monogamous relationship, I don't stray. Sounds like your wife is not going to be open to a poly relationship, and I don't blame her. I think it'll turn into a hot mess and end in divorce. You'll have to figure out what's more important to you.