My parents divorced when I was a teenager. My ExDP's have stayed together, in a miserable, co-dependent marriage that i think they think works for them, but probably would have been healthier for everyone (certainly my lovely former MiL) if they had split up about 20 years ago.
What I realised about this situation recently, when ex and I split, is what it had taught us both about relationships. I knew that while break ups really suck, especially ones when you've been together for over a decade like we had, my parents splitting up had taught me some valuable lessons. I can see that everyone is basically better off after, and able to get along reasonably well. There is life after, and sometimes, it's for the best.
He, in contrast, learnt that you stay with someone regardless, out of commitment, habit, loyalty, whatever - and try and 'work it through', even though he has no idea how to do that, and his idea of it is to just do more activities together rather than actually talk about problems. He thinks, i think, that all relationships are just a bit shit a lot of the time, but you don't split up because you 'love each other', even though I don't know that he really knows what love is - he certainly has only really learnt to express it since i broke up with him.
Anyway, my point is...don't stay together for your children. They will learn good lessons from this if you deal with it healthily.
It's also extremely difficult to engage with repairing a relationship that feels over for you. I wanted to talk, and go to counselling. My ex wouldn't. Now he does, now that we're over - but i (like you) had gone to counselling on my own, worked out how i felt and why, and was done with the whole thing. I feel pretty adjusted to it, and emotionally quite stable, albeit it a bit sad that it didn't work out, while he is devastated, and doesn't understand, still, why we've split up. Maybe counselling to leave would help your OH understand things and make the split more amicable. I just got to the point where I felt like I couldn't make the commitment to try again that he wanted - so i felt going to counselling together was disingenuous. but then he also doesn't really understand counselling and seems to think it's a magic wand that can 'make you' feel certain things (counselling would make me fall in love with him again, just like he's convinced that the counsellor talked me into the split in the first place...)