Good for you Sweetbriar! That was a great response and I really do think it was the right decision. Also good for you for not pointing out that he can just work on reconciling.
Sometimes I just feel like I need to let loose, and one thing I've learned to to draft what I *really* want to say in an e-mail, and then save it in my drafts folder, sit on it for a while, and then give a DB response. Sometimes if you don't work out the anger and/or sadness it can make things worse and for me anyway drafting the non-DB response can help. You can also look back over your drafts and see how your thinking changes, and how what you feel in the moment and assume you'll feel forever actually tends to change pretty quickly.
Snodderly is right, you need to move away from the "will this make him reconsider, will that make him reconsider" type thinking. There is no single event that will make him reconsider, just as there is usually no single cause that prompts them to leave. It's a hugely complicated system. Humans like simple cause and effect relationships, if I do X then Y will happen, but relationships and emotions usually don't work that way.
Nothing will make him reconsider while he has OW in his life. He's not thinking that way now. He's thinking that you're preventing him from being happy by making him feel guilty, poisoning your daughters against him, taking his money, etc. etc. Your goal right now is only to try to keep things from getting worse between you by continuing to DB. Getting him to open his eyes, or waiting for the "fog to clear" will take months to a few years before it happens and that is very unfortunate and difficult. You have to take a long term view.
One other thing to prepare yourself for -- he may tell your daughters that he asked to stay with them one night per week and you said no. You may want to discuss this and why you responded the way you did so that they are prepared. I can't believe he would expect a pregnant woman to move out of her house each week and find somewhere else to stay -- what's that?
Agree with Labug too, stay strong!
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