Disclaimer: I don't own Harry Potter, nor will I ever.
Harry was being constantly hurt. He was sure he was going to break soon.
He was hurt by Ron and Hermione. The way they treated him, they got married and soon forgot how he looked and what his name was. They named their daughter Rose, and their son, Hugo. Harry tried not to let the hurt show when they named Neville godfather. It should have been him.
He was hurt by Albus Dumbledore. Albus only wanted to win the war. He didn't care about Harry, who was being hurt daily and most of the time had to be sent to the hospital because of his "family". Albus just wanted to earn fame and look modest, but discovering Albus' journal, he saw he planned to take the Minister of Magic position; he was just waiting. Albus had a favorite, though: Percy Weasley. It should have been him.
He was hurt by the Weasleys. They were his surrogate family. But then, when he needed them most after the war, he was met with a quill and a piece of parchment: a contract. It stated that the Weasleys could get half of his vault. Harry signed it with a flourish because he thought that they would stick with him. He was wrong. The twins remained loyal, he knew, but Fred died and George never knew about this. Harry wouldn't tell him for fear the Weasleys would shun George. Darren, Ginny's boyfriend, took over. It should have been him.
He was hurt by Peter Pettigrew, Lord Voldemort and the Death Eaters. They killed his chance of having a family, they made innocents go to the Dark Side and start killing. But, they saved people, and Harry knew that if he wasn't prophesized to be the Boy-Who-Lived, Voldemort wouldn't exist due to a long Divination explanation. He should have been a happy boy, a happy boy Harry sees now with his parents laughing at something. It should have been him.
He was hurt by Vernon, Petunia and Dudley Dursley. They were his family, how could they do this to their own nephew? Beat him around, refusing to give medical attention until it was the worst and starve him? Looking down on him and calling him names like "freak" and "burden"? Harry had his emotional trauma start there. He was smart, but he refused to show it. He says incantations wrong, he purposely botched up his potion and he would do the wrong wand movements. He woke screaming in most nights, moaning, groaning, begging and crying until he regained in his senses. His scars were still there, and the word "freak" was still etched in his forearm. Harry stopped believing in fantasies that his parents would miraculously come alive and save him. Stopped hoping that a relative would pop in to check on him and see that the Durlsleys treated him. Remus wasn't allowed because he had orders by Dumbledore and Sirius was on the run. Dudley was lucky he had parents. It should have been him.
And the worst part is, even though all of them hurt him beyond repair, he can't just call them by their last names.
Sirius, Tonks and Remus were the only ones he could whole heartedly trust. Sure, there was Luna, Mad-Eye, Kingsley, Angelina, Katie and George, but he could never turn to them. But, Sirius and Remus were dead. Guilt was the only thing he could sum up their deaths from. Harry desperately wanted to blame someone else, but he knew that he was the only one to blame besides Lord Voldemort. But the greater part was him. He should have known that Voldemort was trying to do a guilt trip. He should have studied and pushed himself further from his limits and master Occlumency. He should have been able to know that he should've protected Remus and Tonks from the war, from the deaths. Now Teddy was an orphan, and it was his entire bloody fault.
He didn't deserve to be Teddy's godfather. He was the one that got rid of his parents. He was the one that practically robbed Teddy of the happy life he was supposed to live. He failed Teddy, and the guilt just creeps in at night, haunting him. Harry never wanted to be a part of Teddy's life; because if he was, he'll end up hurting Teddy more or Teddy will hate him.