You don't remember when it started. When it stopped being about leaving each other secret messages in each other's mailboxes scribbled in crayon and slip sliding your way through his indoor pool even though his mother always fussed at you not to run. Something changed between peanut butter and apple sandwiches and the holographic jumbo sized Valentine's you slipped in to each other's shoeboxes regardless of the fact that you weren't even in the same class.
You don't remember what it was like to not have Eridan. For as long as you can remember, he's been your constant companion. Helping you blow out your candles when you were short to reach the table and being the first one to sign your casts and going as far as to learn how to braid your hair so you could be "the prettiest wife in the world" when you played house. He's always been there, all big smiles and too thick glasses that he couldn't keep up on his nose to save his life and braces all the way until you were in high school.
You used to think he was the most perfect boy on the face of the planet. He never made fun of you or pulled your hair; he always picked flowers for you and held the door open and picked you up to carry you over mud puddles even at the cost of ruining his favorite shoes. He was adorable, wearing his emotions on his sleeve and being too shy to talk to anyone but you, and you loved him more fiercely than anyone else you'd ever met.
But he started to change as you grew up. Sometimes when you'd be out playing, he'd just sit in his swing and stare at the trees, not blinking, barely breathing, not answering you when you called his name. You would get scared and push him out of the swing or off the couch and he would always look really confused, but he never got mad at you for shoving him, so you thought it was okay.
It got harder, when you were in middle school, to snap him out of it. One time while you were waiting out in front of the school for your escorts, you with the latest Harry Potter novel and him resting his head on his arms, you couldn't get him up. You shook and fussed and even hit his hand with your book, hard, and he still didn't move. You thought he was dead, and it scared you more than any horror movie or hide-and-go-seek surprise ever had. You'd started crying, unsure if you should fetch a teacher or call 911 when he finally woke up, and he didn't smile this time, he just held his hurt hand and looked at his feet while you yelled at him to never scare you like that again.
Sometimes he didn't come to school. Eridan had loved school, especially science, and when you'd been in elementary school, his advanced science class had gotten to dissect a shark, and you'd never seen him so excited for anything. But you heard whispers behind your parents closed doors, about how Mr. and Mrs. Ampora couldn't get their son out of bed some mornings, and sometimes he would dissolve in to hysterical tears in the car on the way to school, scaring the driver in to turning back.
When he did come to school, he stuck to you like glue, hiding behind his glasses and your arm, but he forgot to open the door for you now and he never brought you flowers. He didn't even send you a rose for Valentine's Day as per the school's seasonal fundraiser. And it broke your heart, because you didn't know what you were doing wrong and why he wouldn't talk to you and why his eyes were suddenly so sad all the time, shining with unshed tears.
It made you angry. When you entered high school, you joined the swim team and the honor society, and Eridan was like a shadow. His braces came off and you didn't even realize it for a week because he never smiled, only mumbled angrily. Your high school life wasn't without it's problems, girls who you hated and hated you back, boys who didn't understand your flirting, but despite how cherished your friendship had been, Eridan didn't want to hear about it.
He talked about how sad he was all the time, how his parents were always fighting and how he just wanted to run away from home. When you were freshman, he told you that he wanted to die, but before you could even get up from your computer, he said that you weren't allowed to tell anyone because then he really would kill himself and then it would be all your fault (he didn't say as much, but you couldn't help but feel that way).
You'd never been so scared in your life. You were just a kid, living off your parents influence and thinking you were a big shot now that you were in high school, but suddenly you were the only person who knew that your best friend wanted to die. And you wanted to help him, to talk to your mom or your swim coach or someone, anyone, but no matter how your stomach churned and your head hurt and you woke up in a cold sweat at night, you couldn't tell a soul.
And you hated him. Because he was turning in to this monster who you were afraid to leave alone because what if something happened to him? You were all he had in the world, and no matter how much it scared you it was up to you to keep him safe and happy. But nothing was enough, no matter how much time you set aside for him, how you listened to him and smiled and tried to make him laugh, he just kept falling further and further away.
When he told you he loved you, it broke something inside you, because you'd fallen out of love with him. You still cared about him, or else you wouldn't still be here, but you couldn't love him. And it broke something inside him too, because he stopped coming to school for a week, and your parents murmurs told you that he'd had to go to the hospital, and after that, you never saw him on weekends because he was always out drinking, because despite how you'd hollowed yourself out to look after him, it just wasn't enough, and he'd left you an empty shell of a person laying awake at night trying to figure out where you went wrong.
It was your decision to live with him after graduation, because his depression had gotten so bad after he wasn't accepted to the same school as yours that the constant gnawing fear of his death became a screaming waking nightmare. You were wrecked, telling his mother to hide all the knives in the house and shaking in your bed when she told you she would do no such thing.
You were on your last thread of sanity when Sollux came in to your life.
And it's better now. Not fixed, it never can be, but it's better. Your heart doesn't lurch in to your throat when you see him cutting carrots for dinner and when you smile at him now it doesn't feel like your face is cracking. You grab his hand, when you and him and Sollux are piled together on the couch, and when he squeezes it's so familiar and you can smell the daises he would shove in your face, still wet with dew. You wear the ring he got you for Valentine's Day when you were fifth graders on a chain around your neck, a pretty pink-jeweled thing shaped like a flower that was incredibly childish but something you still treasured after all these years, and Sollux just kisses your chest where the ring rests and it makes Eridan smile, weak and watery but genuine.
But sometimes, when you don't have class and both your boys are out, you end up doing the laundry, and you end up in his room, looking at the pictures on his wall. You see his smile, and you can still hear his laugh and the excitement in his voice as he drags you out to the pond behind your house to catch frogs. And it overwhelms you again, the feeling that you failed him and that this is all somehow your fault, and you sit on his bed and cry and cry and cry.