You and Matt have been a couple for a few months. Matt is a photographer and you're his model, which is actually how you started dating. Matt isn't a very open person, the complete opposite of you, who is clearly hypersensitive and dramatic. He's nonchalant and doesn't give a damn. He doesn't show his feelings, or only very rarely. He's always serious at work, so much so that he wants you to act like you're not a couple at work.
Just now, you were at the studio, and there was another girl there, another model, gorgeous, a real goddess. And she and Matt seemed to know each other, since they talked a lot together. But you only learned later that it was his ex and his former model, so you understood that if he hired you as a model, it was only because he had to replace her...
So, you were angry with him, you had gotten home from the studio before him. He got home about 20 minutes after you
"Hey, why did you leave?"