I think the desire for aloneness is healthy, but our society pathologizes it because we have this myth of the ideal of oneness. In olden days, men and women didn't spend as much time together and didn't expect as much from each other. Women hung out together doing their traditional occupations, so did men doing theirs. (RJ, you've read "The Red Tent," haven't you?)
Wanting some time-- even a LOT of time-- alone does not necessarily indicate anything wrong in the R. To me it just means YOU NEED SOME ALONE TIME. Everyone needs that.
I personally think it should be built in to an R, whether you have your special zone of the house (RJ, do you still have that "meditation room"?) or trips alone, or just an evening or two per week when you can do something by yourself-- and I don't necessarily mean going out with your friends, I mean going shopping, to the gym, walking, a bookstore, worship service, or something that nurtures your inner self.
I feel so fortunate that my bf and I operate the way we do-- with two houses, and that we haven't labeled this as a compromise, or settling, or a sign of anything bad. We're spending the weekend together, but tomorrow he will go into town because the truck needs to go to the shop. I'll have the day alone and the night, too. Then I'll go to his house and stay that night because I'm taking night classes at the community college in town. We have a few nights together and a few nights alone every week, and it's never a problem for either of us. I love that this is SOOO simple.
Disclaimer: That feeling of not wanting to go home or dreading seeing your spouse CAN be a bad sign, but not necessarily.
I do remember one time when my late H had gone fishing. I went to the video store and stocked up on chick flicks and foreign movies (he couldn't do subtitles because of his eyesight), laid in a bunch of my fav snacks, and while I was on the way home, he phoned and said he had changed his mind and was coming home early. My heart just sank...and I went back to the video store and returned the movies. I related this story to a girlfriend (a therapist) and she said she understood perfectly-- she had had the same experience herself from time to time.