Rosalie and Emmett had sex a lot.
Jasper always joked that Emmett was one lucky guy, because Rosalie was down to have sex every second of everyday. And when Jasper would joke, Alice would poke him the ribs, with a slightly disgusted look on her face. Esme and Carlisle knew about all the sex they were having—how could they not? Why else would they be locked in their room every second of the day, avoiding everyone? Edward, who hadn't been intimate with any girl for the fact he was either gay or just scared of hurting a human girl, didn't seem exactly jealous of Rosalie and Emmett's relationship, but he always tried to hide a smile when Rosalie walked out of the room in Emmett's shirt and no pants.
And while Emmett was very delighted and willing to have sex with Rosalie, he didn't understand. Whenever Rosalie walked into the room, it was always routine. He would kiss her, softly, then pin her down to the bed. They'd rip each other's clothes off until it was just skin on skin on skin on skin. And Rosalie would grab his face and pull it to his, kissing hard, like she couldn't bear the thought of being without him for even one second. And he'd touch her everywhere she liked, and they'd fuck. And Emmett would be left breathing heavy and lying on his side, saying, "I love you, babe. That was great," between wavering breathes. And Rosalie would sit up in bed, arms folded across her chest with a frown on her face.
Later, she'd go to the bathroom, stare at herself in the mirror. She'd run a hand down her pale, flat stomach, trying to fight tears. Rosalie would curl up in a ball on the cool bathroom tile floor, angry and holding in saltwater. Emmett would knock on the door, saying babe won't you please come out what's wrong, but she would not cry for him. Instead, she'd come out and they'd launch into round two or three or whatever, and she'd kiss him, skin on skin on skin.
She wanted a child so badly, and she knew it was impossible, despite all the sex they had. She would see babies in passing, being pushed in strollers as they cried for their mothers. They cried in hiccups and wails, yet were still too young to have anything to cry about. Rosalie would go to department stores, in search of clothes or makeup, and there would be a young kid running from his mother, shrieking with joy as he zipped past racks of clothes and rows of shoes, and the mother would chase him, a tired look on her face as she grumbled something under her breath and ran after her child.
And Rosalie would watch and try to fight tears. It wasn't fucking fair. It wasn't fair that all she wanted was a baby, but she was stuck in the body of an eighteen year old, immortalized in an encasing of pale flesh, and there was nothing she could do about it.
So she fucked Emmett. Two, three, four times a day.
She thought of children, he thought of baseball.
Sometimes that's the way things go.