Morgan, you are still DB'ing, but you are doing it for yourself and your kids. Not for H. You are moving forward whether H likes it or not.
I am glad you got it all out tonight girl, you needed it. Don't beat yourself up about his mom, you needed someone, she loves you, and she is in the middle because she loves you both. You called and apologized to H, you did the right thing.
Of course H has been through the ringer, look at his day, busted by his W for a secret checking account, busted by his OW for having sex with his W, busted by his mom for being the cheater that he is, busted by his W that he is a liar, basically his W and his girlfriend (Barf!) broke up with him on the same day....need I go on? I hope he feels that ringer. Might be the wake up call he needs, if not to come back to you, then maybe just to live his own life better.