I will continue to say what I have said previously: a couple of months separation would be great for him. I do think that you should tell him that you would like to stay apart, and you would like to see some changes in his life before you do anything with the relationship.
I would start by insisting on regular child support payments ... that would be my first test to see if he really means it this time. Then I would add that he needs to prove to you that he's really "over" Cassie by keeping away from her for this two-month period. You need to stand up for yourself and have enough self-respect to take control of your sitch and not be a doormat at his beck and call as he bounces back and forth between you and her.
Quote: Where's RB to smack me and say I'm just being bitter and holding a grudge?
I would never smack you for saying that your H's behavior is not trustworthy and you don't believe that you should "give him another chance" because he'll just blow it. That's actually very logical and part of a good decision-making process. I've had a problem in the past when you've expressed hatred and anger toward him, because that isn't helpful to you.
Good luck!
The LORD is near to all who call on him, to all who call on him in truth." (Psalm 145:18)