Brahma's attitude towards Dev could be one reason for Gaurav being in a same sex relationship. Though geneticists believe that humans have a gene that makes them predisposed to homosexuality but the acquired predispositions are always there- that's why perhaps we have heterosexual males and females. If this is the case, it could bring Gaurav closer to Vidya as I see that Gurav has a rocky relation with his partner and he has shown affection towards Vidya.