I totally understand, I have felt the same on many occasions.
You have had the rug pulled from under your feet (to put it mildly ), you have been 'bombed' there is always going to a period of shellshock and then rebuilding. It is totally natural to be the way you are feeling at the moment.
I will say though that you need to stop thinking in victim mode. Why should you get acknowledgement for things you do for the kids? They are your kids. Do you/ did you thank her for the things she does? I'm not suggesting you start doing that btw... You need to stop looking to her for reassurance because you ain't going to get it.
Have an honest look in the mirror and work on yourself if needs be. For me, it was building up my self confidence again. I realised that the girl I saw in the mirror, the one that was pursuing, being walked over etc etc was the total opposite of the bubbly, confident person I really was and that was because all my focus was on my h not on the important person - me. The only person you can control is yourself. It is her problem if she is still spewing and her feelings are her responsibility, your feelings are yours.
I'm confused, what is it that you are doing that could be the wrong thing? Surely she is the one who is initiating divorce, having an affair etc.
I feel your exhaustion at all the decision making. Come on here if you need support. Start posting to other people and build a support network, it will really help and it will be the only way to build it up. It is daunting at first but it will help.