Shortstory about a moonbase

[StianTrygve]

Hi, I am looking for a shortstory that takes place in a moonbase. I read it in the 80s, but I have no clue of when it was written. It is told from an «I-perspective». The protagonist is living in a moonbase with a group of people, one of them his gf. He discovers that the rest of the group has started to believe that they are NOT on the moon, and that it might be safe to go outside. He tries to convince them they will die, he points to the low gravity where they are, but in the end they leave. The story ends with the protagonist sitting alone, watching a piece of paper fall slowly to the ground, saying that it is beautiful to watch. Does anybody have the writer and title?