You can be. I'm basically aromantic heterosexual myself; I have a sex drive but no desire to enter a romantic relationship. While romance and sex often go together (people generally want to have sex with people they have feelings for), you don't necessarily have to have one to have the other. **** buddies and hookers are things.
That's probably a poor explanation, but when we have all these different nuanced gender and sexuality identities, I don't think that aromantic hetero/homo/bi/sexual is unfeasible.
Doesn't not having desire to enter a romantic relationship just mean that you're not looking for a relationship? Aromantic implies that you don't feel romantic attraction to people at all, at least that's what I think word should mean, a la asexual, amoral, atheism, asymmetry.