My wife is one of four. Her brother is on #3, one sis has 4 exes the other married twice, widowed on second time.
My younger brother was gay (deceased), other married 50 years and a widower.
Our parents divorced after we two older kids had left home. My father stayed because my mother was so unstable and he knew in the 60s he’d never get custody. Needed to protect us.
You do what you have to do for the best of the children. That’s what I always told myself and what I tried to live by.