"I want closure. Let's go back to being monogamous." Dick stroking her hair.

A few months ago he asked to open the relationship. You refused, and after much insistence, you gave in. The first person he slept with was one of his ex's.

Well, after a while you accepted it and started having fun, without him. And now he feels disappointed and frustrated by the distance between you.

He wants to close the relationship because he feels like he is losing you because of his choice.