Not married, and never been in that situation living with a partner, but I have slept on a couch, simply because I don't sleep well, at all, toss and turn all night, but no one asked me to, I just prefer that.
On the subject, I can imagine even from my light weight experiences in relationships, when you are angry/they are angry, the last thing you want is to be that physically close.
I can recall in a hotel once, someone tried to get into bed with me, and I didn't leave, but I felt like physically repulsed/dread that they were that close to me. That was the last night we were together. So i get it.