You break your bone and he takes care of you
Ashton: you write this thing for English Class but now you just broke you hand by falling off the stairs. There was no way in hell you'd be able to write a full text with at least seven pages with only the left hand. So somehow, when Asthon came home to cuddle with you, you got him to write whatever you spelled. At least he was fast at keyboard and it didn't take too long.
Calum: your knee was totally broken and you could not even walking without a fucking weel chair. You were simply hating it: it was too much, you were able to walk, why all that scene? But obviously neither the doctor or Calum got too happy with the idea of you walking around. Because of that, your boyfriend was crashing at your place till you could finally walk again. He'd do everything for you: even giving you a shower and carry you around the house.
Luke: one of your ribs was broke and it was pressing your lungs, what mean you could barely move, just for precaution. Actually, Luke was more terrified than you, and all the time would ask if you could breath well. "Babe, it won't press enough so I would stop breathing, ok?" you always said, but it was not enough for him. You just thought it was so cute seeing him all worried about you.
Michael: "I just broke my pinkie, okay, it's not like I can't even carry a drugstore bag." you said to your boyfriend when he tried to grab the thing from your hand. The two of you had just left the doctor and even though your broken bone was hurting a little, you weren't useless. "I know, but I wanna spoil my girlfriend so I can charge her after." Michael said, smiling when you slapped his shoulder softly. "Perv."