Harry had known from the moment Ginny told him she was pregnant. Honestly, he had probably known before that night, where she grasped his hands as they spoke quietly over dinner, her hands squeezing tightly. So tight that her fingertips were turning purple. Harry knew that the baby wasn't his, wouldn't ever be his, couldn't ever be his. But Ginny didn't.
And she was just so happy. Her eyes shone while she was pregnant with James, eyes bright and alive and willing to be a mother. She wanted it so badly, Harry could feel it every time her stepped into their home. He didn't know if she was still seeing him. He convinced himself that maybe it was a one off, that Ginny had just wanted the baby so badly and had realized, subconsciously that something was wrong with Harry.
Something had always been wrong with Harry.
He hadn't known until after their third attempt at having children, until after Ginny's third miscarriage. That he couldn't reproduce because of Voldemort. Because of what he had been. He had punched a wall three times, and broken his hand in six places when the healers told him. It was his fault Ginny couldn't get pregnant. It was his fault the baby always died. But it was always his fault.
And so he didn't say anything. The night Ginny told him she was pregnant and that the Healers said she was stable, Harry had stopped dead and become as cold and silent as the grave. It wasn't his baby. It would never be his baby. And so he never told her, and they both lied a little bit more everyday to cover up the gaping raw aching hole Voldemort had put between them.
And then James was born and Harry almost didn't care who the child's father was, who Ginny had made this beautiful baby with, but he cared enough to order the potions required. He cared enough to prick the baby's finger and perform illegal blood magics to see the name spelled out in painful scarring letters on parchment paper. Seamus Finnegan. He broke his left hand that day.
And perhaps, that would have been the end of it. Because no matter what Ginny did or said or fucked, Harry was convinced that he loved his wife. Until she got pregnant again.
He almost stopped coming home. He almost walked away the night she told him they would have another beautiful bundle to call their own, another gorgeous son who looked just like his Papa. He stopped sleeping, stopped talking, stopped being much of anything for a long time.
And when she gave birth, he used the potion again, confirming the nasty taste at the back of his mouth and the butterflies in his gut as a name that obviously wasn't his blossomed forth on the page. Darren McKingley. Ginny's Quidditch boss. He stopped sleeping in the same bed as Ginny. Stopped sleeping in the same room.
Harry was perhaps twenty six when he noticed it though. Something incredibly strange. James was three, Albus was two, and Ginny was pregnant again with a daughter who was not his child, but he noticed a gray hair intermingling with Ginny's red locks. He started looking around at the people around him, Draco and Astoria, Hermione and Ron, Luna and Neville. He really looked hard and noticed something incredibly peculiar.
They were all looking older.
It was perhaps the most frightening thing Harry had ever noticed in his life.
They all looked older, and he didn't.
When Lily was born, Harry couldn't bring himself to use the potion again. He simply stated that he was happy with three children and smiled tightly at his wife. The smile he received was equally tight. Ginny didn't ever have another child. They never had sex again either.
Harry made excuses until Lily was eleven. Both to himself and to Ginny, and although Ginny's never asked for a divorce and neither did Harry, he knew they both wanted one. He sometimes wondered if Ginny had told the other men that she had had their children rather than his own.
When Harry turned thirty seven, he knew that calm before the storm was over. Lily was no longer an apt excuse now that she was old enough to attend Hogwarts. Besides that, Harry was miserable. He had been miserable for a long time.
Divorce was not his first solution. It wasn't his second or third either, as all three of those options had been both variations of the same thing but only became further confirmation of what Harry had feared all these years.
He couldn't die.
He couldn't have children and he couldn't die.
He filed for divorce later that week.