When the war first broke out, Harry declared that he didn't want to be a part of the war. So he went into hiding deep underground, as Voldemort took over the world. Although Harry didn't want any part in the war, he would do anything to end it.
Anything.
Whilst Harry was hiding for the war he fell in love with a man- a werewolf- Fenrir Greyback. The man who had killed thousands of children and ate them.
Harry was immediately smitten.
Hell, Harry was ready to give up the entire Potter fortune for this... Man.
Harry's godfather Remus did not approve of the pairing. However Remus not supporting them didn't stop Harry and Greyback from getting married, no matter what no one was going to object to the marriage. Except someone did. Bellatrix Lestrange, fresh out of Azkaban and Harry's ex-lover. She came running into the chapel objecting to the marriage, declaring that she'd always loved Harry and she wanted to be with him forever. Harry was overjoyed, he thought that he would never see Bella again. Harry ran down the aisle, practically skipping into Bellas's arms. Greyback was glad that they would be adding another person to their relationship, the more the merrier. Harry was finally free from the unwanted grasp of Voldemort, he had his true loves beside him, holding onto him, and he was free.
Together the throuple had three children, one each, James, after James Dean. Rodolphus, after the Renaissance scholar. Fenrir, after the child of Loki. The family would go on monthly picnics under the light of the full moon, whilst James and Greyback hunted their prey. They had Christmas roasts and birthday parties in the campfire lights. They lived long and fulfilling lives, right up to the moment they died peacefully, the throuple holding hands in their large bed, taking their final breaths as one.
And then Harry woke up. Gasping for breath he struggled to inhale, legs twisted in the linen sheets, a cold body sleeping next to him. Harry's perfect life, far away from Voldemort, had been a dream. He was stuck in a world where he was forced to marry Voldemort to end the war, where his loved ones were dead and he woke every morning next to a breathing corpse. Harry quickly pulled himself away from the bed, away from Tom, and towards the bathroom, tears staining his face.
Standing under the scalding water, Harry mourned a life he never got to live, a life of love and happiness. Even if he didn't win the war in that alternate world, he would still be with Bella and Grey. Their children James, Rodolphus and Fenrir would be alive and happy, he could go back to picnics under the full moon whilst his wolves ran wild and hunted stray rebels.
Instead, he was stuck with Tom Riddle, a man with no nose and yet the noisiest personality.
Harry had no children, no life, no freedom.
He was locked in a glass cage.
He was undoubtedly trapped.