Think carefully about what you do that makes a difference and what you do that doesn't make a difference. Don't believe the cr@p about "wanting to be with you," while still living with her. That's obviously stringing you along. He just wants a back up in case OW dumps him and you don't want to be that.... what you want to do is teach him a lesson. That if he's gone, your life goes on and you are going to be one hot mama with or without him. You mentioned the difficulty of creating a new life for yourself with a baby, but if he died tomorrow that's exactly what you'd need to do.
Love your baby. It's a special time, it goes quick and you don't want to miss out on it. Get extra help from parents or in-laws and start connecting with friends and making friends. Go to the gym regularly (helps get those endorphins going).
Don't answer you phone.... and when you do be busy. You have sounded weak and needy in the past and he knows this. Although it's really not wise to date now, you can hint to him little things like.... "Wow, I never realized I was so attractive. Guys must have radar and just KNOW when you're separated or divorced...." Make sure you say this informationally and not in a way that sounds like you are trying to make him jealous. After you lay one of these comments out then quickly change the subject. And if he asks for details just say, "Oh gosh, I'm still legally married, of course I'd never date someone while I'm married. But it's kind of interesting to see what's out there now while I'm separated... " And then change the subject and refuse to say any more about your life.
One of the best peices of advice I recieved was BE MYSTERIOUS!!!!
Be busy, and don't tell him every little thing about your life. In fact, don't tell him anything. Just be a great listener and ask lots of impersonal questions so he enjoys talking with you. Let him confide in you.
There is no arriving, ever. It is all a continual becoming.