Coconut,

I agree with Zeus to a point about W doing some temp checking and blame shifting. Yet on the other hand I still think you that you could save your M. To me, I strongly believe that DBers should give the process at least one year to try and save the M before throwing in the towel.

I would add a bit to Zeus recommended response a bit more and come from a place of authencity:

"Transitions like this can be hard on everyone at times. With time I know we will all be in a better place."

Here's an expanded version:

Thanks for sharing. I am too sad about all of this. To be clear, it takes TWO people to make a marriage work. I do not think that we are able to meet our own needs in the marriage--especially for me to feel emotionally safe with you. Transitions like this can be hard on everyone at times. With time I know we will all be in a better place.

This puts the ball squarely in her court on whether to step up, taking full responsibility, and being genuinely remorseful for her choices to engage with OM.