I'm not sure I can say for certain, because it's only been a year for us, but it was a similar situation, although I pushed for it, he probably would have kept trying but it was over for me. He knew it was too, it just took him longer. I'm lucky as I'm still in the house, but that will change in the next year or so, we did decide not to do it all at once though.
He has been brilliant about finances, so have I, I do have lots of resentment about the fact he's earning shitloads and only has to have the kids mostly when it suits, plus I'm actually due more from him than I get, but it does all seem to be working out...I have times when I think it would have been easier to stay together, but it's easy to forget the bad times and all the niggles that made me fall out of love with him. Kids are 6 and 11 and are very attached to me, he was always at work and wasn't that present when he was here. He's definitely autistic and can't do emotion, unless he's drunk..I still like him, but I outgrew him.
However, things we do that mean the kids have been relatively unscathed...
I bite my lip if he's being useless, I save moaning about him for my friends, the kids never hear of it.
I involve him in all the school stuff, do all the admin, even if it galls as he never did it before and it hasn't changed..I let him know about everything and he chooses what to actually do, I do need to stop reminding him about parents evening etc, but then they'd lose out.
I make sure that we appear as friends in front of the kids, but we don't hang out together just with them, for example birthdays etc are fine together and even with my family, but no days out etc,so we don't confuse them.
I facilitate contact, so I do all the pickups and drop offs, as he doesn't drive. It's a pain, but it means the kids get more time with him.
Partners, we are both seeing people, but the kids don't know, and won't for ages. It's separate to our time with them.
I send him photos, he sends me them too, of stuff they do together. Means I can talk about it with them.
We have a routine, I warn them in plenty of time if it's changing...they both enjoy time with him, I try not to get upset about his Disney dad behaviour, or the fact they don't brush their teeth, or wash properly at his, I just make sure they do here.
I kept a good relationship with my ex in laws, I send them photos and chat, I've known them 20 years and I think it'll continue, they've not taken sides and neither have my parents. I downplayed the reasons to our friends and family so they're all on good terms with us both.
I try to be present as s parent on my time with the kids, it's a 5/2 split, generally, it does mean I end up with all the drudgery, but with a few very late nights I can keep work stuff out if my time with them and I just crash when they aren't here, I sleep a lot and then I can be up and with them when they are.
Basically I'm married still without living with him, it's still better! I'm still resentful but I have my two nights to just kick back and I do think eventually they're happier, although covid and everything have meant their lives have changed, I don't think the separation has actually caused much damage. Once things are back to normal I think I'll be able to tell properly though, obviously big holidays away and lots of spare cash for stuff aren't there any more but we make our own fun when we can. I definitely do more for him than I'm happy with but it's ok, it's for them.
Not sure if that helps! Good luck though, it's a process, there are hurdles along the way but I think the saying goes, you can't eat an elephant 🐘 whole, just take it bit by bit..