You and Sam were getting closer, since you had more in common then you and dean. Dean didn’t mean to get jealous but it was hard when his little brother and his girlfriend had more of a bond than his girlfriend and him.

His last straw was when you three were getting a motel room after a hunt. The front desk man had asked if you and sam had needed a room away from dean and dean snapped. Taking the key for the separate room and dragging you along.

In the motel room, he grabbed his bigger shirt and held it out to you. “Here.” He knew you liked sleep in his shirts every night. Dean was jealous, of you and sam but didn’t want to show it.