I feel the same way you do about my marriage. People would ask me if I was happy (this was before the BD). I said “well, I’m only unhappy because he’s unhappy. If he was happy, I’d be happy.” Huh? Short answer is “No. I was not happy.”
I was at that place as well. It is not healthy. If you haven't already, I recommend you read Codependent No More. That is something you can work on for yourself.
W 34 Me 42 Married 7 years together 8 0 kids 1 beloved dog BD 4/6/2018 I moved out 4/7/2018 I moved back in alone 8/05/2018 I file 3/06/2019 D official 5/7/2019
