~from Narrator's POV~
(Y/n) did get better, much to the staff's surprise. Not much - the nurses and staff would whisper about how death was inevitable anyway - but enough to stand on her own.
At that time, Eren kept his promise and formally confessed to (y/n) who, true to her words, accepted him.
***
All of their friends - including members of the basketball team (especially Koganei, Furihata, and Sakurai) - stopped by to visit as much as they could, but nobody visited more than Eren. Every day, he'd go and talk with (y/n) or just sit by her bed, holding her hand.
Levi and Himuro came in almost every day as well, but they didn't get to spend as much time with (y/n) as Eren did.
After six months of surviving, Eren finally proposed to (y/n), and - like their earlier promise on the day that Eren had finally found out the truth - she said yes. They were married a week later in a spare room of the hospital, with Levi escorting (y/n) down the aisle in a wheelchair and Himuro serving as the best man. Also in attendance were Mrs. Jaeger, who was crying the entire time; Hanji, Sasha, and Mikasa serving as bridesmaids; Koganei, Furihata, and Sakurai; and surprisingly enough, (y/n)'s father, who had also started visiting (y/n) regularly and patching up their relationship.
Of course, when he heard about the wedding, Levi made it very clear who would be walking (y/n) down the aisle, no questions asked.
***
(Y/n) was never able to leave her hospital room after that. Her condition took a turn for the worse - and the turn after that, and the turn after that. Still, Eren visited every day and always made sure that he could smile for his beautiful but sickly wife.
And then came the day that it seemed the entire hospital had been holding it's breath for.
***
The heart monitor was the first to notice, and the boy sitting beside her the second. He was numb; he'd known the day would come, had tried to prepare himself for this...But the pain, while expected, ripped him in two.
And yet...when he thought of her, when her lungs still toiled to help her breathe and when her heart still worked to pump, he didn't think of her pain or her tears or her sickness. No, he saw her smile, desperate and hopeful.
He'd known this day was going to come; he'd known that it would break him in two, but that hadn't stopped him from falling in love.
He'd do it all over again if it meant he got to watch her smile just one more time. He'd do it right this time and not waste all the opportunities that he had with her, every chance to hold her hand and smile at her and watch her smile back. He'd watch over her and always be there to catch her when she tripped, to hold her up when life was dragging her down, to keep her safe from the world. Of course, knowing (y/n), she'd probably insist that he was just being over protective like her brothers, but he was okay with that.
As long as I'm alive, I'm going to protect your memory because that's my right as your husband, over protective or not.