Sorry to hear you are feeling sad; these sound very valid reasons for leaving. No wonder you were unhappy.
My reasons for leaving are very similar. My DP was great in the beginning; fun, caring, successful career etc. Looking back, there were probably warning signs I missed.
As soon as I moved in, the mask started slipping & the selfish, disrespectful behaviour started. Lots of passive aggression, not able to communicate clearly & honestly.
I should have run for this hills at this point, but I had committed & moved away from my support network.
He contributed so little over the years, just immersing himself in work & cherry-picking the nice parts of parenthood eg coming home just in time for bedtime stories after I'd slogged all day at work, plus dome dinner & bath. I was run ragged.
And then the mental health issues, which he had never told me about until 5 years in to our relationship. He had multiple job losses, time off sick, we had huge financial difficulties which put me under greater strain.
And then I found out he'd had an affair in the past.
I had counselling on my own - I would highly recommend it, OP, if you haven't already. For me it was life-changing. Horrible to discover I had co-dependant traits, and he was quite far along the narcissist spectrum. It helped me understand why I put up with all the crap.
I just couldn't do it any more
& told him.
The separation is ongoing but I have no doubts I have done the right thing.
You have done amazingly well to come through this. You are worth more.