I'll tell you what would clear his mind faster than anything - you dating someone else.
NOT that I'm recommending bringing another person into this mess- but I guarantee you, if you were dating, and your S was playing with an OM --- your ex would suddenly wake up and smell the coffee.
So - how to get there without involving another person? By giving the APPEARANCE of dating. Bring S over when you are all dressed up like for a date - and rush out of there because you have to "meet some friends". Have flowers sent to your house. Don't be available for his calls when he has the baby. Or answer them from a noisyt party or bar. Or play a TAPE of a noisy party or bar in the background when you take his call.
