There are quite a few people I know who live alone in their later years, by choice.
It takes a lot of work to keep a marriage together. Some get lucky and find the right partner.
I would think most marriages fail because one partner grows OUT of the relationship, or because of infidelity. Power struggles seem the least of the problem, because if you have enough love and care, you move through those problems.

I know a lot of strong women.
None of them are in marriages.
I would marry again if I found an equal but I would never be subjugated to a man.
Nor would I tolerate infidelity from a man I loved.