So, most people/clients are all over Matt 'cause of his hottness and he's kinda used to it. But one day one of their clients or someone they have to work with is trying to get into Foggy's pants and Matt is NOT amused.
Cue Matt being a passive/agressive jealous asshole and Karen just wanting to kill them both.

Then sex :)
Bonus if it's first time.
Extra bonus for bottom!Foggy.