Focus on you... doing whatever you need to do to make yourself happy.. in interacting with your H somehow you need to forgive him for walking out.. and work on being friends. Whether you get back together or not (which I hope for you and your daughter that you do) being friendly to each other will help your daughter through this bad scenario so much.
It isn't easy being a friend.. For me it's only become more normal now.. initially it felt really forced.. it still feels odd that my H and I are becoming such good friends. but that I can't really tell him my feelings.. 'cause I don't want to push.. and a real and open friendship would allow me to do that.. not there yet and not sure we will be for a long time.
Anyway, that is my $0.02.
Thinking of you! You can do this!
Hugs, W2G
PS. Realized with my previous post that I totally missed your update post that your internet was fixed... and all the interaction with your H.. my post sounded so lame after I realized I missed yours. Sorry about that!