Written after watching Season 12, Episode 3 "The Foundry". Spoilers if you haven't seen it yet although I do add my own 'dark' ending that does not happen in the show.
Excerpts in italic are taken right from John Winchester's Journal by Alex Irvine.
I Don't Want To Be Here Anymore
Mary rolled over on the bed and stared at John's journal still open on the desk. She imagined it couldn't have been easy on him when she died especially since it was so horrifying but to read that Dean wouldn't talk or that Sam wouldn't stop crying, how was she supposed to process that. John constantly wrote about how he imagined having a daughter, or if they would have more children, and on every May seventeenth he'd scribble down what anniversary it was supposed to be. She had missed out on so much.
*Mary will never see Dean hit a home run. She'll never see Sammy walk, or hear him say his first words. She won't take Dean to his first day at school, or stay up all night with me worrying the first night he takes the car out. It's not right that she's not here, and that's all I could think about today. I'm so angry I can barely see straight-I want my wife back.*
John was out for revenge and although she couldn't blame him he had pulled their boys into a world that she had done everything in her power to keep them out of. Dean had a .22 in his hand at the age of seven. Seven. Her little Dean was supposed to be playing baseball and teasing his brother not learning to shoot with what John noted as a killer instinct. *But sons have to be soldiers. And soldiers adapt.* He had always talked about his days in the marines but promised that he would never push it on the boys; turned out more than one promise was broken.
Sitting on the edge of the bed she scrubbed a tired hand over her face trying to get her mind to quiet even if for a brief second. The bunker was home for her boys but to her it was a cold, dark basement filled with books to keep them locked in the supernatural. Dean's music had stopped playing about an hour ago followed by soft snores and Sam must have finally put the book away since his light was no longer spilling into the hallway.
She grabbed the journal and carefully walked down to the main room in hopes of not waking either of the boys. How could she even be sure that this was all real? There were phones without cords, computers that could fit in your hand, and nine different flavors of jerky according to Dean. It seemed that only two things that stayed the same; the Impala and the fact that there would always be something that went bump in the night to fight off. Dean and Sam had answered any question she had asked but they were still holding something back. She was their mother. She was the one who was supposed to be sheltering them. This couldn't be real because she had gotten out. She had started a picture perfect family in two story blue house with white trim. When she had burned on the ceiling John hadn't believed I ghosts let alone knew what a shapeshifter or reaper was yet her boys had started and ended the apocalypse.
The journal in her hands was the only thing she had to go on. Sure, the boys had answered what they could but the words on these pages were real and raw and some times covered in liquor stains when the world had gotten too much for him. She read that at seven years old Sam shot a deer but it wasn't the fact that he had shot a gun but that John had written Sam thought he had to protect his brother. *I'm the kind of father who shows them that when it comes to family, you go to the ends of the earth to put things right.*
Sure Sam and Dean were grown men now but I their thirties they should have been married and starting families of their own. This wasn't the life she wanted for them and she knew she didn't have it in her to start all over again. She left the journal on the table with a note she hoped they would understand. Although they were her blood, they weren't her boys. Her Sammy was six months old, her Dean only four. These men in front of her had a life in front of them that she had no place being a part of.
She should have known better, Mary thought with a deep sigh as she drove through a Kansas she no longer knew. Once a hunter, always a hunter. You are never truly out and she was foolish for ever thinking she could have anything that resembled a normal family.
This was her fault.
*Mary, I can't fight every minute.*
A single tear rolled down her cheek as she pressed down on the gas pedal even more. Just maybe tonight she could out run the evil that lurked around every corner. Her boys were strong, intelligent men that had already mourned the death of their mother. Certainly, they would be able to do it again. The light turned red, she closed her eyes, and the last thing she felt was the glass shattering across her face.