Sleeping single in a double bed

I think I had Barbara Mandrell's 8-track with that song on it in the 70's. Sleeping single in a double bed. I had no idea what I was singing. Barbara was my hero. And my first concert.

Now I know what that means...yes I do. 

When I was married I slept on the right side of the bed. I don't remember why. Maybe he preferred the left? Is the man supposed to be closer to the door for safety? Funny how I was the one to check out the noises. Now I sleep on the left side. I am still checking out the noises.  Actually - to be honest I sleep diagonally. I take up the whole bed.

Why not?

I think for the right man I can shut the diagonal off...and sleep in the middle.