There is, I would strongly suspect, a difference between an individual simplifying and a couple simplifying. The good thing about the couple scenario is that the other person can help you see the places you are holding back, whereas an individual usually has blinders on when deciding what he/she really needs. On the other hand, only an individual can, in the end, make the hard decisions on what to get rid of when it comes to his/her belongings.
Yesterday Ed noticed 3 boxes of quilt magazines on the landing. "Three boxes? Why do you need to keep quilt magazines? Where are you going to put them?" So I find myself having to justify keeping 3 boxes of quilt magazines. Then I start to second-guess myself. What if he's right? What if they have to go? Waaah! Well, he's not a quilter, so he wouldn't understand.
And it's the same with his end of the bargain. Every once in awhile I'll take something of his I know he'll never use, etc., and put it in the give-away pile, then he retrieves it, saying he cherishes it, then he'll give me the long (usually boring) story about why.
So a couple keeps each other on their toes about facing reality, but some decisions just have to made individually in the gut.