Thinker ~ I agree with A&K....about Mrs. Thinker battling her own demons. Who doesn't, really?
But trust ME on this - the other piece is the M you and Mrs. Thinker made together. That would be the things she did and the things she didn't say. That would be the things you did and didn't do. That would be all of the junk under the rug that finally tripped y'all up.
It's not JUST hormones or postpartum or depression or selfishness or any other "hook" to hang this on. It's two people who love each other but stopped loving (action verb) each other. The fall out of that is ... well... that's why we're all here.
I agree but you can't always fix this for someone (or ever really), you just be your best self and IF they have the capacity to meet you there, they do.
However, in my sitch, I am going to push hard for counseling for both of us. For the sake of our kids.