That makes sense - but I think you are in a different spot than many of us.
For several of us, there is a struggle to transition from mono to poly. It is that transition period where one partner feels a change is necessary and it can be traumatic to both. I would still be stuck if I thought my wife was just being stubborn in not choosing monogamy.
For better or worse (haha) I think most married partners do feel that they need each other on some level.