Dean would be lying if he said he wasn't disappointed when Sam told him that even though he loves him, he doesn't want to have sex.
He understands why, without Sam having to explain in any capacity. The kid has been through a lot, and Dean doesn't want to push the boundary.
He's content to just cuddling like they did when they were kids. He's content enough to place soft kisses on Sam's forehead in the morning. He's content to call it love, even if it's convoluted and unlabeled.
Sammy doesn't need to be Dean's boyfriend, or his husband, or his boy toy.
He's his brother and that's enough for Dean.