I am in a much better place today. There are things I will never understand, mostly the 'why' and how he can't see that I could never meet his unvoiced expectations. Some things aren't meant to be understood, only accepted.
Ep, most of us roll around in the why pit for a while. I did. And truth is, I still don't know why. STBX's stated reasons for having the affair and leaving me were 1) my closet was messy, and 2) my weight had fluctuated throughout the years while I was having his three kids. (I am not overweight). Yep, I'm guilty of both. But believe it or not, it was only with the help of my IC and some good people here that I realized that some men see a closet as functional storage space and not a character flaw, and that the changes a woman's body goes through while having children do not make her unworthy of love.
If you feel like there's some "why" that's related to you, for instance, you ate bon bons and sat on the couch all day and neglected the house and the kids, or if you nagged him mercilessly, or you withheld sex, well, then, there's some work to do on you. If the "why" is related to him, just accept that you may never understand. And climb on up out of that why pit. There's a better life ahead.