I'm going to add to the discussion by also saying, apart from Kunal redeeming himself, how will Mauli ever be able to trust him.
Sure, EMA's happen. Got it. People can also possibly get back together (not on this timeline, I've mentioned this before. A reunion would have been more realistic immediately after the affair and when Dida was trying to make the marriage work vs. now after Drashti's exit/Nandini's death).
But apart from the redemption angle, or rather as an extension to it, Kunal has said a few times that Mauli did nothing wrong, she was a good wife, etc.
Going off of that, how will Mauli be able to ever trust him again, because he cheated even on a "perfect" her.
What I am trying to get at here is, they either have to show Kunal apologizing for the EMA and saying it was wrong/not divine OR
Them explaining what led to the affair, i.e. what made Mauli and Kunal's relation so weak.
Let's say an EMA happens (because unfortunately they do), and the husband can explain his thought process such as "You weren't home enough and didn't have time for me. So I met XYZ and we began spending time together and I felt important and relevant again." then now we have the cause or the emotional/psychological reason figured out. Then the natural progression is going to marriage counseling, having the couple rediscover their strengths and weaknesses and work towards a better marriage and better themselves.
I.e. - This was the problem (lack of attention from wife to husband) which led the marriage to become weak and not running at 100%, problem is identified, marriage counseling and change in behaviors/habits are figured out i.e. the solution, and on the road to a repaired/recharged marriage and back to 100%.
In this case, in the episodes when the EMA was first exposed, Mauli asked Kunal where she went wrong and he said no where, then again when Dida was trying to get them to work the marriage out and there was that pooja/event when Kunal told off this other pair of siblings? I think who were gossiping about the affair (Kunal was wearing that navy blue kurtha, I remember this scene explicitly) he also told them Mauli was a perfect wife, and even post-leap the day when Mishti told Mauli she hated her for not letting Mishti meet with her Popsy and Mauli broke down while Kunal could over hear on the phone, again he mentioned Mauli was never at fault.
So basically, here the EMA and Maunal marriage is not being sold as - there was a problem (with a fixable solution), it's being sold as a picture perfect marriage where Kunal just got attracted to his wife's best friend dancing in the rain so much that it didn't even make sense to him, apart from the fact that it was meant to be/divine with Nandini.
I.e. - The marriage was perfect and running at 100% yet still an affair happened.
So whose to say that Kunal won't cheat again? If he can cheat on Mauli, after a picture perfect, running at 100% marriage, then whose to say he won't do it again?
Let's say he does apologize this time around and says he loves her, etc., well he said all those things before the EMA right? But still ended up cheating without cause or reason. So how do we know he won't do it again? That's why even his love confessions towards Mauli won't do much for me at least as a viewer, because he has made love confessions to her prior to the EMA. I rather much see him apologizing, debunking that Kunan was divine and saying it was lust/a mistake, etc., giving some reason or logic as to what transpired and why it transpired (i.e. identifying a problem), and what will change the second time around if they are remarried/why he deserves a second chance (i.e. a solid solution).
Cheating is wrong no matter what. But at least if there is an identifiable problem in the marriage, the couple realizes it and works towards bettering their marriage. A reunion then is much more easier to gulp.
In this case showing an already picture perfect marriage, with no evident reason for cheating was hard to gulp. And that is why Mauli trusting Kunal again, even if he makes promises of love again, will be harder to gulp.