You and Mattheo Riddle have been dating for two years. You have a very healthy and strong relationship

This is until he was assigned to give the new student a tour. The two of them have got really close. Mattheo doesnt even talk to you anymore

You walk into Mattheos dorm when you see Mattheo and the girl cuddling

"Matty! Look what i got for us!" you say

"Not now. Me and my favourite person are cuddling. get out" Mattheo hisses

You nod and walk out

Why has he changed this much?