Hold Onto This Lullaby by broken_soul
The thing is, Harry knows Louis doesn't like himself. Actually, he really hates himself, as he told Harry somewhere at the beginning of their relationship, when he was crying into Harry's arms and finally letting himself lose control after what seemed like a lifetime. Louis told him back then, just like that, just those three words that broke Harry's heart. Between sobs, that is. It's just that Louis not liking himself is hard enough to handle for Harry - he can't make himself think of it as hating. He thinks that if he did, he'd break completely.
And it's not like Louis has a reason for that. Harry told him hundreds of times. It's just, Louis' mind keeps telling him otherwise.
Once, after a really bad day, Louis locked himself up in their bathroom. He turned on the water, but Harry could still hear the muffled sobs through the door, and he knew Louis was sitting on the floor, knees pulled up against his chest, like he always did. He spent hours - at least it seemed like that to him - pleading Louis to let him in, on the verge of tears himself. When the older boy finally opened the door, Harry had him wrapped in his arms in a second. He kept telling him he was okay, he was fine, everything'd be fine. After Louis calmed down enough, he didn't stop, told him how much he loved him, how beautiful and amazing he was. He knew Louis didn't believe him. He told Harry he loved him, too, even more, and when Harry said it was impossible, he shook his head, bit his lip, but stayed quiet.
That was the moment Harry realized Louis wasn't really fighting those thoughts, that he let them take over. Or maybe he didn't let them, but it happened anyway. It was also the moment Harry swore to himself (and later to Louis, too) that if Louis wouldn't fight them, he'd do it for him. So from then on, it became a constant battle between Harry and Louis' mind.
When they were doing a photo shoot a few weeks later, all five of them standing next to each other, Harry knew something was wrong. At that point, he was so used to looking for any bad signs in Louis' behavior that he spotted one immediately after it had appeared.
Now it was Louis looking down at his shoes for a brief moment between two takes, and before he could hide his face under his fringe, Harry saw that look on his face, the one full of disappointment and failure and helplessness and sadness, so much sadness. He couldn't do anything there, though, and when Louis looked up again, he managed to put himself together.
Harry didn't let it go, though, so when they were finally alone, he sat Louis down on their bed, holding him tight in his arms, stroking his back. After a long time of "Louis, what was it" and "talk to me, Lou" and "please" and "tell me what's wrong" and a lot of "nothing" and "nothing, really," Louis admitted he felt bad about being shorter and smaller than the rest of them. If it wasn't for Louis' teary eyes, Harry might have laughed because, honestly, that was one of the things he loved about Louis' body the most. Which he told him, of course. Which Louis didn't believe, of course.
"I look stupid," he said.
"You're gorgeous," Harry corrected him. "I love it that you're shorter than me. I love how adorable it looks when you want to kiss me and have to stand on your tip toes to reach if I don't lean down. I love how I can wrap my arms around you so easily, how you just fit there, like we were made for each other. And I love how it makes you weigh less than me because I get to pick you up. I love all of it. I love you."
"I love you, too," Louis said after that, blush appearing on his face. Harry knew he was just trying to distract him from continuing. Louis didn't understand why he thought all of that. Harry would make him understand.
