Hi OP, I was also in a 30 year EA relationship, 22 years married and I totally identify with that feeling of having wasted your time.
I'm 5 years out of the marriage now (mid fifties) and TBH that is what irks me the most. I don't miss him or being in a relationship or living with someone, but I do feel seriously pissed off at the time I wasted with someone who got his kicks from abusing me.
After a lot of counselling I do understand how it happened. We met at uni and I just did not have the sophistication or the resources to identify the issues. I had overly domineering parents which mean that my natural inclination (even now, though I'm working in it!) is to assume that the other person is right and I am wrong. I hate confrontation.
My exH did me a favour in a way as I found out he was a long term cheat on top of everything else so that precipitated the break up. I can see it's much harder in your case when you are almost waiting for a triggering event.
What I can say is that my life now is infinitely better though. I don't ever want another relationship with a man, I have never had any doubt about that. I have teenage DC who live with me including one with SN who will probably never leave home.
I do love having my own home with my own bed and the freedom to read if I want to (although reasonably bright he never read outside work and used to bitterly resent any time I spent doing it), to have baths late at night, to build up my female friendships and to work a lot for charity, which he sees as a pathetic waste of time :)
I think there are two great things which have come out of my past though and I think they are common to most women who have been through something like this and will be to you too:
- I am fucking titanium now as I have rebuilt myself from the ground up. My exH did everything he could to make me and the DC homeless and penniless and still periodically has a pop at it because money is the most important thing in his life. I am seriously good at the legals now and I take no shit from him over anything. I do feel there is nothing life could throw at me which I cannot deal with and I don't sweat the small stuff any more. My starting point is that everything gets sorted out in the end and everyone else can fuck off. It's a nice place to be.
- My female friends have been the most awesome experience of my entire life. Even women I only knew slightly rallied round and have been, and continue to be supportive and fantastic. At my age we have all gone through lots of life's crap in various ways and TBH I think there is nothing more awesome than a decent, sensible, middle aged woman who cares for herself, her family and her community. The world would fall apart without us!
Sorry, all of that is a very wordy way of saying: seek support in counselling and in your friends, plan a good time to leave (this Summer after exams sounds good), and concentrate on building yourself the life you want just for you, not for anyone else. It will be fabulous, I promise.