A lot of people probably stay married just for the kids, even when they are in unhappy marriages. I can understand that because I can't imagine not seeing Charlie and Olive every day. When I was in the hospital with Olive for a week, I felt like Charlie changed so much!
It's usually the moms who get main custody, but if your SO did and you could only see your LO on the weekends, would you stay in an unhappy marriage to be able to see your kids?