I've been reading your story for a very long time now, and you've been getting some very wise support and guidance.
I rarely post here anymore but there are a few things I feel compelled to tell you. Partially because I find you ignoring the advice you get, and partially because I see a lot of my old situation in yours.
The first thing you need to do is stop calling him. You can't force him to send you a pack of diapers or a check. You can't reach through the phone to his wallet, and you are smart enough to know this. You are using this as an EXCUSE to call him, because you cannot stand not having your say.
I fully believe that you are addicted to this drama and you have no idea what you really want. It's fine if you don't know what you want, no one expects you to be perfect, but let's just call a spade a spade and get on with what YOU need to do.
Your constant emotional upheaval and anger can most definitely affect your children. In fact, I would be very surprised if it doesn't. They already have one parent who has let them down and put their own selfish needs ahead of their well-being. Don't make it two.
You say you want your H dead. That you are mad at the world. That he has abused you, lied to you, and you fear for the safety of your daughters because of his temper. But if he called you up in the next ten minutes and begged to come home to you, you'd do it. Don't pretend it's otherwise.
That's not a healthy relationship by any stretch of the imagination. It's more like an obsession.
So how do you stop?
First, quit playing the victim. You made your choices, you've stayed with him through beatings and verbal abuse and infidelity, haven't you? Did he hold a gun to your head to get you to do this? No. You need to cowboy up and face reality. You are not in this situation because he forced you to be. You knew what you were getting into. Take responsibility.
Second, STOP CALLING HIM.
You can't force him to come see his daughters.
You can't guilt him into coming back or apologizing.
Right now, your calling is only accomplishing two things. It's keeping you spun up in a constant state of high anxiety. And it's PROVING to Kevin that you will chase him down and beg for contact, even bad contact, no matter what he does to you.
If you don't change, Emily, there's no chance for your marriage. More importantly, there's no chance for you to be happy on your own.
If you change your way of thnking and your REACTION to him, Kevin will have no choice but to try something else. Right now the two of you are locked into a sick pattern of ridiculous high school drama. STOP IT. If you stop it, then he has to. If one person walks away from the chess board, the game can't continue, right? So walk away. Stop calling him.
Your emotions and your self image are totally dependent on your H right now. But what you don't see is that you have a lot more power than you think you do. He isn't doing this to you at this point; you are.
Honestly Emily, you are a mother. The time for this nonsense is in the past. You should be focusing on your daughters, taking them to the park, finding free stuff for the three of you to do together. You should not be sitting agonizing over every single thing your H and the OW are doing. I promise you, when your kids are older you will kick yourself for wasting this precious time with them, on those losers.
One thing I do admire about you Emily, is your wilingness to come back to this board and take hard talk. I know you are trying. But so far I haven't seen you take one proactive step toward changing this sick cycle and action/reaction with your husband. You can't go more than 48 hours without leaving him nasty voice mails and demanding his time.
Start by going one day. Just one day. Don't call him, take a call from the OW, respond to any MySpace messages from her trashy crew... don't do it for one day.