I'm not sure if I'd consider myself asexual. I'm a male and I'm 'attracted' to females, and that seems to suggest that I am heterosexual. However, despite the attraction, I don't really feel any sexual urges. It's more of a "Oh, yeah. I guess I'd agree that she is pretty" sort of thing. I typically don't even think about it unless someone brings it up ("She's attractive don't you think?"). Even then I try maintain some sort of objectivity and end up being unsure of whether or not I'd consider the person in question as attractive.
Perhaps, I am heterosexual with asexual tendencies.
Personality type more likely affects the presentation/interpretation of our sexuality rather than our sexual orientation. Following this line of reason, INTPs' sexual orientation would be logically analyzed, determined to be clouding rational judgement, and this could lead to a manifestation of asexual thoughts and behaviors. Thus, INTP's appear to be more apathetic towards sex. Then again, INTPs are human and, like any other type, could just as well give into their sexual urges since they are evolutionarily rational and unavoidable.