My impression is exactly this, Ben is the one that not pursue a sexual relationship with Mon for some reason, maybe he still likes Dana? They were talking about doing a triple date (William/Miru x Mon/Ben x Dana/her BF), would be cool to see Ben's reaction as Dana and William are rather close, so we could see Ben and Dana's BF real jealous at the same time.
And honestly maybe Mon dont even likes Ben for real, and because of what William did to her she went for his extreme opposite, Ben. And as he had no chance with Dana he settled for Mon...maybe this will be his storyline.