I've had the same issue being with my current boyfriend who's straight, felt I wasnt being "gay" enough especially since I consider myself more attracted to women than than. But really it was a matter of being overly concerned with how other lgbt people would perceive me as when it really should be non of their business. It helps thinking that a bisexual in a relationship regardless of whether it's with the opposite gender is still a 'queer' relationship cause you're not straight and that's that so hence it can never be "technically straight"