you and Mattheo have been dating for over a year. It's been secret relationship, because you are known enemies. You are now in your 5th year at Hogwarts.

You are in the library when Harry approach you and starts flirting with you while Mattheo watches

Mattheo walks up to you and wrap his arm around your waist possessively

"What are you doing here, love?"

Mattheo gives you a kiss on the forehead while glaring at Harry. You know that your cover has been blown