Bruises (Pray to the Masochist)

"The bruises, missing work, canceling plans, and the weird behavior." Sam's voice softened considerably, he looked at Dean with pity. "I don't care that you're gay, but I'm not going to sit back and watch my brother be in an abusive relationship." In which Dean has been keeping secrets, Sam makes assumptions, and misunderstandings almost get Castiel arrested.