Harry: Begin Again/Taylor Swift. You both had had your relationship problems in the past, so you we a bit wary at the beginning of your and Harry's relationship. Both you and him were somewhat cautious with how you acted and what you said, but soon you became a lot more comfortable with him. You realized that this relationship might actually last.
Liam: Still Into You/Paramore. He would always make you feel butterflies. It didn't matter if you were a month and a half into your relationship or two years into it. You felt like you were permanently stuck on 'crush' mode, and honestly, you didn't really mind that.
Louis: Beside You/5SOS. Long distance relationships sucked. Only being able to talk with your boyfriend through a screen or a phone got rocky at times, and the directioners weren't all that accepting of you. Louis didn't want to leave you alone, but he always had to. In the end, it made your relationship and trust a bit stronger, though the fans never completely warmed up to you.
Niall: I Want Crazy/Hunter Hayes. You two didn't have the typical relationship. Right from the start, you two know that it would be a lot different than previous relationships. You absolutely were insane about each other, though, and it helped make a healthy relationship, even though you were miles apart.
Zayn: Chloe/Emblem3. You had always been insecure, and always compared yourself to his ex's, or your friends. You finally opened up enough to tell him that, and he hugged you, and hugged you for a long time. He couldn't make you feel better, but he could try.
