N.
G.,
Did he have this work situation before you had children (or even before you were together)? If he did, then I think that it is going to be hard to get him to understand that you want him home. From his point of view, this will probably be something that you should have anticipated as it was what he was doing before you had the baby.
It sounds as if you need to have a conversation about how willing he is to change jobs. If he isn't willing it is going to become a huge problem if he feels forced to change. If he is resistent, then you should probably see what you can do without him to help you out when he is gone. For example, can you (or will he???) pay for someone to come and help you out a few nights a week or on weekends? Does your hospital have a program to help new moms? Mine does and I understand it is wonderful.
The bigger questions, of course, would be is he willing to change jobs and if he isn't are you willing to stay with him anyway. Before tackling those, try to find ways to make your life a little easier so you can think on those questions with a clearer head. Good luck!!!