I have heard of a few famous artists and scholars who are married and choose to live apart. Frida and Diego lived next door and had a bridge that connected their houses, which was a lovely gesture, I thought. Of course, none of these couples had any kids either (as far as I know).

It's not something that works for me, but I don't think it makes those couples who choose it any less "married." I suppose it depends on what your view of marriage is.