Background in my introduction (important for context--I've never actually physically or electronically cheated, despite years of wanting to).
Today, I told my wife that I had been having feelings for other women. I told her of my guilt and shame over not being able to NOT feel these things. She said that she has never once had feelings for another man.
She said she's had suspicions when I've talked about various things that women I know did or said on some of the trips I've taken, or when I've worked exceptionally late in the office, but because she trusts me, she trusted that I'd never done anything with any of them.
I told her that it was especially hard when I was here in a new city in a new state by myself getting set up before she and the family moved down, but I still never did anything with anyone.
I told her about my fears, my not trusting myself to avoid getting emotionally involved with women as I develop friendships. I asked if it was OK to let that leash loose a little, and she said that as long as I don't cross the line, it would be OK. I said that it's been a very difficult line to walk, and it all came to a head: she asked if I was cut out to be a married man, and I responded, "Not in the traditional sense." She is most emphatically against the notion of polyamory, having said that she refuses to share me with anyone else--she won't be the stay-at-home wife that I come home to after being out with someone else, and she requires a divorce prior to me seeing anyone else, even though I told her that I do not want to end our marriage. I decided not to press the issue for now with any of the descriptions others have posted here of how they've made it work, in particular in how they've made their long-term mono partner not feel like a housekeeper while they go out and have fun. I don't think that browbeating will help.
I think she wants the idealized me that I pretended to be, rather than the person who I believe I really am. I don't want to hammer her with the statement that I've tried for a long time to be who I thought she wants me to be, and it actually hurts me--the one time I mentioned that, she mentioned divorce again. I'm feeling blackmailed, and rather than feeling closer to her, I now feel like an outsider in my family.