Dude, STOP!!! Stop with the mind reading (I guess her needs are being satisfied, etc, etc., ) You are so wrapped up in HER you can't see past your own face. Put boundaries in place for your emotional protection but stop planning out the separation/divorce unless you plan on filing tomorrow. Wait until your anger and resentment have colled (or at least can be compartmentalized) and then CALMLY approach your wife about the mortgage payments and stuff. Detachment is the key.
In the meantime what are you doing for yourself? It seems like you are obsessing over this OM instead of working on making yourself both emotionally and physically smokin' hawt! BE the man that others would be like, "Hey if you don't want him I DO!"
M 10yrs T 13yrs BD #1Oct 2015-PA between WAH and COW BD #2 April 2016-WH resumed PA, she broke it off Jan 2 2017 WH says he wants divorce April '17-Letting go 2018 D busted DD8, DS6, DS3