Happy Together (1989)

Christopher leaves to pursue a career in writing. Due to a computer mixup he shares a dorm room with Alex whom he presumes is a man. However, Alex is the beautiful Alexandra! When upon first meeting her she gets on his nerves by partying and being with different men while at school! She is very outgoing. Christopher tries to get another roommate but while trying to get switched, she helps him in different ways by improving his love life and writing ability. The both of them fall in love with each other, but Alex has a boyfriend Slash who comes back for her. After putting her name on the wall of a men's bathroom, she realizes she is better of with Chris.