Perhaps I am a WAS, in that I'm the person who is initiating the divorce and am walking away from my marriage, although it was my husband who had an affair. He wants us to save our marriage. This might help spouses who were the cheaters but now want to reconcile and start again.
I don't know your spouse, but for me, cheating was the dealbreaker. Not only was it a dealbreaker, my stbx-H and I agreed that it would be deal breakers from the time we were dating up to throughout our marriage to now.
From my perspective, there is absolutely nothing he could do to make me change my mind. There is no "task" he could do - marital counseling, flowers, being remorseful, etc. - that would change my mind. He asked something once (paraphrasing): How sorry do I have to be to win you back?
The problem is that regret/remorse/changing himself is not the currency that would stop the D. It's just not relevant to this whole sad situation.
Like I put in another post, when he asks that makes as little sense as someone asking you "What car should I buy?" and someone answers "3:30pm."
I don't want to be a finger-wagger here, and there seems to be a lot of good advice. But I wanted to share my insight with those who might be in a similar situation and give my perspective.