My (33M) wife (33F) and I are going through some relational issues due to our seemingly foundational disagreement about ENM.

We’ve been married for five years and together for eleven. I’ve expressed my desire for ENM for effectively as long as we’ve been together. She has implied similar interest by mentioning things like MFM fantasies and her own evolution on the idea, but has never been comfortable actually opening the relationship. I've never pushed the issue, as the stability of our young family has always been my priority. Now, however, I have finally reached a place where this is something I want to actively pursue.

We've talked, we've tried couples therapy, nothing has worked in dissuading my desires or reassuring her fears. She admits that her primary barrier is her own insecurity but retreats to emotionality whenever we try to confront it. She also adamantly claims that this is not something she wants, despite her previous hinting to the contrary. I'm left wondering whether this is a fundamental incompatibility.

I understand someone not wanting to participate in ENM. I don't understand someone not wanting someone else to participate in it. At the risk of preaching to the choir, I can't fathom the mindset that views sexual possession as a prerequisite for a healthy, loving relationship. I promised her before our marriage (Which, it's worth mentioning, she valued and strived for more than I did. I've always primarily focused on the health of the relationship and never needed the validation of a title.) that, if monogamy was the price I had to pay for her, I would. I stand by that claim, but I feel increasingly duty-bound and can't understand why she thinks that my love for her should preclude interest in all others.

Do we have mutually exclusive definitions of love? AITA for destabilizing our relationship by pursuing this? Can a one-sided open relationship work? Does anyone have a similar experience with a happy ending? Are we doomed?