Sometimes I think about how Sam and Dean often get parallel storylines where Sam is interacting with a woman and Dean is interacting with a man. Prime examples being Benny and Amelia but also the siren episode (yes yes I know the male siren is supposed to be a stand in for the brotherly relationship he wants but come on the connotations of it being a man are still there). There are some lesser interactions; mint condition, Sam and Girl Sam, Dean and the horror movie nerd. Don't even get me started on Dean's grief at losing Cas multiple times being paralleled with Sam's various romantic interests being killed off (Jess, Eileen, Rowena). But one I don't see a lot of people talking about is Sam/Ruby vs Dean/Crowley.
Sam has an explicitly sexual relationship with a demon that coerces him down a dark path. Dean has an explicitly sexual (the unforgettable night with the twins) relationship with a demon that coerces him down a dark path (the entire moc to demon!dean arc). Sam turns to Ruby when Dean is dead and he wants revenge and Ruby uses that to her advantage later when Sam and Dean are destabilized because they're fighting. Dean turns to Crowley when they need to eject Gadreel from Sam and then Crowley uses that trust to his advantage when Dean and Sam are fighting about Gadreel. They even refer to it as Dean and Crowley's summer of love.
Also, I hate to say it but the only difference between a lot of Sam's relationships with women and Dean's relationships with men is that because the male characters are more fleshed out, the relationships are vastly more nuanced, with the exception of samwena because Rowena was a character in her own right before she was entangled with Sam. Ironically, I think the reason samwena had more depth is because the romantic nature of their relationship was never said out right, it was treated the same as destiel almost, they shared a profound bond and a deep understanding of each other that no one else could quite penetrate.
