I really feel for you. This thread is at the same time sad and inspiring as you are on a journey to try to find a better situation for yourself.
I am now late fifties. Ten years odd since I left my ex husband. What a journey that was - and I remember being stuck for years in the place where really all I could see was keeping things going and getting the tea on the table for my daughter.
I don't regret leaving for one second - although the practical side of it was unbearable difficult at times.
Right now - I am making another transition. DD the last year of sixth form and launching her to Uni - with all the practical and emotional things that entails. It is an exciting journey though - as well as at times a really stressful one - I've had to think very hard about what I would like the next decade or so of my life to look like. I'm also staring a house move in the face - which is hard too - but I hope will be an improvement.
I'm conscious that potentially I hope I will live until my nineties.
You are seventy. I totally get what you are saying about being afraid and stamina and so on. However I hope you will bear the following in mind:
If I compare life with my ex husband with now - no matter how much work it is raising a teenager and running a household by myself - it is MASSIVELY less work than it ever was with my ex husband.
Reason being exactly what you have described. I realised much later that he would deliberately be uncooperative, uncaring, not help with all sorts of things and that these were his deliberate actions to make life more difficult for me.
This was abusive - and when I left this came to the surface more - also there had been no caring or physical intimacy for years. I remember quite clearly that even a hug stopped when my daughter was born. This is an awful way to live.
There is no doubt whatsoever that leaving may be scary. But you will also find in the next life transition more than a few surprises - the kindness of strangers, new friends, new interests, new freedom.
Some people are afraid to 'be alone' in the later stages of their life. Personally I would choose 'being alone' in a single person household over 'being alone' in a relationship where the other person doesn't care about me.
Sometimes when I do go out - it can appear as if the whole world is in coupledom - the couples I see out and about seemingly in retirement and so on.
If you look more closely though - you can see couples sitting at restaurant tables with absolutely nothing to say to each other, staring at their mobile phones etc.
I would like to think that in the next few decades of my life I find greater meaning than that. I really hope you find your way with this one.
There is also the thing that coupledom and marriage does not last for ever either. There are plenty of widowed people out there. Plenty of people like me who are embarking on a next phase of life - after the kids leave home.
I can't pretend it is not scary - it definitely at times IS scary. But generally when I'm feeling as if the whole project of my life is very daunting I switch the radio on, chat to my daughter, get myself out, make a list - of things to do and in the background I'm so grateful I never have to argue with another person who is supposed to be an adult male - about the housework that needs doing.
Sure I have blips with my daughter, but to me that is different as she is only sixteen and still learning.
Adult men should know better.
And you deserve better than this OP.