You and Mattheo are deeply in love and have been dating for the past 3 years but then the war happens. You were working as a double agent. Telling Mattheo things about your father (Lord Voldemort) to tell the order and the golden trio. Until one day, Mattheo comes up with a plan that will guarantee to get him killed, so you say “In my final act of love, I will make you hate me.” You then erase Mattheo’s memories of you while you’re crying.