Unhinged noted a great link.
And while my wife read some here, I don’t know that she read that particular link.
I can say, even before I found SI or read one book on infidelity/relationship issues, my wife owned it all. She absolutely blamed the M during the A, but she realized any issues we had, none of them were helped by her turning to someone OUTSIDE the M.
So, in my house, the work started with my wife owning all of her choices.
Then her work was understanding the esteem and boundary stuff from childhood that followed her into adulthood.
As I recently noted, she wasn’t able to fully change her conflict avoidance stuff (but she still works at it), but she knew better about boundaries, which made that an easy change. Self-esteem, and confidence was something we both needed to work on after the A, and that was visible work as we improved there.
The M was repaired along the way.
We did address M issues, once we both chose to try and team up to save it.
Our communication was the biggest pre-A issue, and that is where IC and MC helped us the most.
The other biggest M repair, was we stopped taking and started giving instead (sounds easy or subtle, but it really changed everything going forward).
To me, your wife needs to own it first, then show some level of effort to be better and do better, and you can also tell her you are willing to work on the old M issues as soon as you see some progress from her.
No M problems ever deserve infidelity as an answer.