His band is asked to provide the music at this wedding. And leading up to the wedding he's getting kinda freaked because a lot of famous people will be there so this could be the band's big break. there's a lot of pressure from the other guys in the band to really focus so they can give the best performance ever and in the process the stress kinda gets to him and he starts getting angry at every little thing. the stress starts getting to him and even though he's not outright mean, the tension that starts to build up around him starts affecting his relationship with Cassie, to the point that she starts avoid him just to get away from the constant bickering they've been doing. She's afraid he's going to leave her like he's done to all the other girls. Like he said he would when they first started dating. And she just doesn't want to deal with that. He doesn't see her at all before the wedding and tries to see her the day of but her cousins tell him to get lost and leave her alone cuz he's just going to start another fight and then leave forever and put her through even more pain. He doesn't get to see her until she's sitting at the reception and he's up on stage. So, in the middle of the reception he asks the guys to play a song with him and then sings this really sweet apology song to her expressing everything he hadn't been able to put in words before. how sorry he is for the fighting. how much he loves her. how lost he is without her. how she's the first girl he can't picture the rest of his life without. And after that he steps down from the stage and over to where he is and tells her "I'm not asking you to forgive me because I know I don't deserve it. But would you at least dance with me? Give us a chance to start over?"