So sorry. You know, you don't have to respond at all if you want to talk to him. If you don't respond he'll have to call you. It's up to you if you want to do e-mail or phone. Since H seems bent on divorce at this point and is proposing an informal settlement, you may want to get a consultation with a lawyer at this point just to understand your rights. You don't have to do what the lawyer says, you don't have to hire them, but at least have them sketch out what a settlement usually looks like and what the negotiating levers are.
No need to be the "nice person" right now -- he cheated, he left, he wants divorce. Your needs should come first now, be fair, but don't go out of your way to make things easy for him.
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015