I am in your precise situation - false R (twice) totaling about 15 months. I left about 2 years after the last discovery of the ongoing A (the first year was to save money and get myself sorted out and the second was due to COVID or I would have stuck around about a year as opposed to two). Fast forward almost 4 years, WH has been in IC for him - we are no longer married, but we are reconciling our friendship and date occasionally. I moved a 20+ hour drive away and have not moved back so our dating is not frequent but neither of us are dating anyone else (we can but we agreed to inform each other if that happens - I have not and I have no reason to believe he has). I have no plans to move back at this point, and I am not making "all" the effort to see him - in the last year it's been much more his effort than mine, and I will admit that the fact that he has custody of 2 of our 3 dogs (I have the other along with a foster) is part of my motivation to go to our former house where he still lives.
I have posted quite a bit about his/our journey. He is definitely a different person that the person he was, which at the end of 2019 when I originally was scheduled to start actually moving away, was very similar to this that you described (with exception to #5 below - my WH admitted that he wanted the A as he liked the attention etc and that eventually he felt like he was in love and wanted to run off with her sometimes):
1. He invested absolutely no time in thinking about it or sitting with the pain. He was scared of upsetting me or dealing with hard things.
2. He had very little empathy for me - he hated me being sad but never really got what he'd put me through because he never thought about it. (This is the one he's now doing)
3.He drowns in self pity and feeling sorry for himself and can't see this is an extension of the selfishness of the A
4. He doesn't understand his true "whys", and still reverts to trying to blame outside circumstances OR self pity (eg: I am sorry I am such a terrible person. He admits he made 101 bad decisions but doesn't know "why".
5. He still can't be honest with either me or himself. He still denies he wanted an affair ("I just wanted a friend!") Obviously if you just want a friend you don't have sex with the person
6. He reverts to anger and self defensiveness if he's criticised and can't just sit with it.
7. He can't fully accept that he killed our relationship and on some level tries to blame me for being sad and angry
8. On some level he feels entitled to forgiveness or me meeting his needs and he struggles to be humble and selfless if he's feeling like the bad guy
I would say now, after almost 4 years of IC and a lot of self reflection, I can say he has done a ton of #1 above, and doesn't do #3 at all anymore. As to #2 definitely has empathy for me, and seems to really grasp, to the extent anyone who hasn't been through it can, how his A, and more importantly all the lies during false-R affected ME. #4 and #6 are a bit of a lifetime work in progress but he really has accepted his flaws and is actively working to change them and he really tries to address his defensiveness and accepts criticism much better than he ever did, about anything, which is a major plus about the "improved" version of him generally now. He accepts he destroyed our relationship - like blew it into an unrecognizable mass and wants whatever we have going forward to be better. I forgave him so if he feels entitled he has my forgiveness anyway, but realizes that I have been changed by his lies during the A and False R forever, so to the extent he does not like some of the new me, he is responsible for some of that and I will not apologize for it (example, there are some movies/tv shows I just will NOT watch anymore because of the way they downplay and or glorify affairs - too bad that one of them is a movie we used to love to watch - not happening anymore for me and it's not up for discussion).
Right now, we speak, but I've told him that for me things feel over. I dont really feel able to believe that he might really do the work.
When I was getting ready to leave at the end of 2019, before COVID screwed up my plans, I felt just like you said above. I was DONE. He started IC for him, because he claimed that he wanted to understand how and why he did this - like what inside him allowed him to have the A to begin with and then treat me like his arch-enemy (he referred to feeling like he was a spy during false R - having to cover up how he "really" felt about me and not let on what he was doing because I might out him and ruin all of it - and because he thought he was doing me a favor by sticking around since I really seemed like I wanted to make it work ). During 2020 when my moving plans (and moving for work plans) were delayed he was in IC and I started to notice a change - and in all honesty it was being present for that time that made me consider continuing to even talk to him once I moved. He even travelled to help me pick out the house and made getting things funded easier, drove one of the dogs down and brought other stuff, and seemed simultaneously happy for me and the awesome place I bought and sad that I wasn't going to be around everyday. Now he jokes that my place is much nicer than his, which is where he lives now and where we used to live (he's right it is WAY nicer), and that we can live at my place when he retires (which is like 10 years from now). Whenever he says that now I laugh and in honesty say "Maybe. Who knows?"
Had I left in early 2020 as planned IDK if we would be where we are today, as my plan was to leave and never talk to him again, not out of spite but because I really had nothing left to say to him. Because of COVID and the disruption of my work plans my plans to leave were delayed, and so I got to spend a year with the "really going to IC for him' version of Mr. TISL and the changes were all good - had he done this in the beginning, heck, even after d-day 2 and the year of false R, maybe I would have stayed, but he didn't, and my resolve was not broken. Once I was able to move for my new job, I left. It's still better that I did leave I think - I have been able to be me and am able to deal with things on my terms.
So I say leave - none of us here have any idea what will happen with you and your WS - but if you leave and he stays the same, then you have done yourself a favor. If you leave and he makes changes then YOU can decide if you want to come back, or you can be like me and end up in some sort of self-imposed happy limbo, or maybe you will find that you just want to move on. Whatever. Most people on here, after seeing years of my posts dealing with my WH congratulated me for moving. I don't recall a single person saying "maybe things will change for the better with you two anyway" but alas, it did. I can't tell you what will happen with you either - but from my experience, taking control of your life and moving forward on your own terms brings a peace that is very hard to obtain if you stick around.
See my signature line below...
[This message edited by ThisIsSoLonely at 5:31 PM, Thursday, September 14th]