I think my friend is being a jerk?

one of my roommates is being a total pompous ***. he is part of a fraternity and every weekend he brings my other roommate to go partying with him and his frat brothers. He has never once offered me to go with them. Ive been friends with him for five years. Whenever ive implied that i would like to go with them he says "they would get mad if i brought more than 1 person" then this past week he brought my roommate and another friend of ours who goes to a different school. I implied that i would like to go but he said "they would get mad probably". Ive been friends with him since before he joined the fraternity. also the house we live in belong to my parents and gave him a great deal on rent. i feel like he somehow thinks he is better than me for some reason.