I think Antonia has given you terrific advice and feedback, and I entirely agree with her. Our sitches are quite similar - long marriage and kids, but I am much further on timewise. Time heals and brings its peace, especially if we help by doing teh spadework, as you are doing.
One thing I would take issue with is your sense of being stuck in spinster mode, as if this was a bad thing.
There is dignity in being on your own as a woman. We are so stuck in the idea of coupledom, that we forget all the single people who live happy and fulfilled lives. It is easier to portray them as weird/embittered/perverted. but that isn't the reality. As Antonia said about her parents - together but stuck in a dysfunctional relationship. And I see many couples like that.
Hollywood always has romance on the agenda, but fails to celebrate any other mode of living, and we buy into that.
My xh is no longer 'centre stage' in my emotional life, and it is so good to have got to that point. Give yourself time. My life is so full now, that although I still miss what I had, which is human and understandable, I no longer am pulled down by regrets.
Approve of yourself and your life choices. You have class and dignity.
