There's no denying that love is involved in most relationships. That love, however, is no different than any other kind of love. The same emotional connection that you might feel for a best friend can also be felt for a romantic partner. The difference between a platonic relationship and a romantic relationship is not the kind of love between everyone involved; it's whether or not the two parties are sexually involved. Sex is what catapults a relationship to a different higher level of intimacy, thus allowing what could be a strictly platonic relationship to become romantic. The physical connection is what breaks down the walls of friendship and allows a romance to blossom.
This leaves no room for asexual relationships. There are plenty of people who identify as asexual who have prosperous, long-term romantic relationships. Insinuating that sex is the true marker of a romantic relationship does not account for relationships where sex 1) has never been present or 2) has been been present.
Sexual desire does not equate to romantic love.