I think it is not so much fog, but it is because we still love the spouse. I am not talking huge, I want to be with you don't leave me love, but the kind that stays from spending years, sharing secrets, having kids etc.
Unless it is truly acrimonious, and no one grows because of it, there is some love that remains and we are always willing to give that person a bye, so to speak, on some behaviours that would have us bringing a boot down on someone else.
