What are people thinking?

I'm wondering why do married couples stay together in a failed
marriage. Whether it be mental or physical abuse that they deal
with from the spouse. Or another example could be there is no more
love left between the two of them. They live their separate lives,
maybe sleep in the same bed but probably not. The #1 reason given
in both cases is because of the kids. #2 It's convenient & wont
involve lawyers or clean out your bank account. What other reason
is there to stay?

I've been through my own personal experience. To this day if I
think about it, I'm not sure exactly why I stayed.
The ex & I were together for 24yrs I was 5yrs older. After we
were together about 6yrs most everything about her changed.
I was unaware her mother & grandmother were bi-polar & now
she was showing signs. She had some tests done saw a shrink
& was put on meds & group therapy. Still not the same person.

1yr before the split it was living hell. I had stood by her
& was there for her all that time till it got to the point
where she wouldn't listen to me or any one else. That's when
I'd had enough. I've always been a somewhat passive guy, but
by the last month when the house was sold we couldn't be in
the same room. All I could hear was her & how everything was
my fault I screwed it all up.