You always knew Cedric was a player, there wasn't a single person on Hogwarts that denied that, but when both of you began dating, you really thought he would change

Oh, how wrong you were

It took it's time, but nearly 6 months into the relationship, your best friend showed you a picture of Cedric and Cho Chang making out before his Quidditch game

As soon as you saw the picture, you stormed towards him, not caring who he was with or where he was