Just got to thinking from another thread. There's quite a few threads around with people unhappy in their marriages for whatever reason, thinking about affairs and what-have-you. The overwhelming consensus is "Leave so that both you and your OH can then be happy separately."
But how does this work? If you have small DC, who is the one who leaves? If a custody case ever came up, then the person who leaves automatically has a black mark against them. And who has the financial stability to just go and rent a flat - we're talking deposit, rent up front, bills, connection costs etc.
I'm genuinely bewildered at the number of people who think it's ok to say "just leave" without thinking of the bigger picture and the logistics of the whole thing.