You can influence the WHAT, but you can't influence the WHEN, dawg.
You influence her decision by being THE best man, fully confident in himself and interested in (even passionate about) his life, and who is the absolute best father he can be to her children. That's the "what" part.
But the "when?" This is HER journey, and she will come around if and when she decides that the lure of you and her home is stronger than the lure of her affair. YOU CANNOT CONTROL it, and as a man I found that extremely terrifying.
Still, I DID accept it, I DID press on, and you can too. But no, there are no magic bullets here, dawgy, but I suppose you already knew that.