Buy some good toys, like a vibrator and a dildo, and seek out another boyfriend for yourself.
The more important issue, as I see it, is the children and the fact that he wants to father more with these other chicks. What's that about? Spreading his seed? Weird.
Your libido and sexual satisfaction can be taken care of in another relationship. Don't focus on that right now. Focus on the baby-making issue, and his role as father. Does he let his obligations and responsibilities slide because he's concentrating too much on boinking these other women?
You might want to request that you and he go to therapy together.