@Richtea67 another thought even though it’s directly about your marriage and possible divorce.
When I was working, I used to push myself like hell to be able to carry on working. As a result, I had no energy left for anything else. Weekends and evenings were just used to recover, staring in the empty space. I was constantly in survival mode, didn’t enjoy anything I did with the dcs and family because all my focus was on physically putting one foot in front of the next.
When I did stop work, it’s because I simply couldn’t do anything at all by then. I ended up lying down 22 hours a day, unable to do more than getting up to eat.
Now, in retrospect, I wish someone had told me it’s ok to stop work. It’s ok to say that spending quality time with your dcs, family, dh is more important.
I wish I had been told how benefits work because I’m only entitled to ESA through sheer luck. I know many disabled people who have pushed through, reduced their hours only to find they are now not entitled to anything at all.
You are saying that you are only holding in with your finger tips. I suspect this also means everything else in the house, the kids are asking you for a tremendous effort.
Please, regardless of whether you separate or not, consider stopping work. Work out your benefit entitlement (the ESA isn’t mean tested as it’s linked to your contributions + you can still work up to 16 hours a week).
Sincerely, I would have had a much better life quality if I had stopped years before I did. Money wise we wouldn’t have been much worse off. And I truly believe it would have had a positive impact both on the dcs and on dh too.
(and yes the idea of organising some time with just your dh made me smile. When you are so tired, organising an evening out and then spending a couple if hours of quality time, interacting with someone etc… is simply out of reach - or only at a huge price re exhaustion and pain)