Dreadromantic may or may not be seen as part of the aromantic spectrum. A very simplified definition is that a Dreadromantic individual would be romantically attracted to someone, but as soon as that romantic attraction is realized, the person in question gets extreme anxiety or dread.
It is different from romance repulsion because someone who is repulsed by romance is often repulsed by the viewing or consuming of romantic content, while Dreadromantic is purely defined by attraction. However, a Dreadromantic individual may be romance repulsed, but not all romance repulsed individuals are Dreadromantic.
The sexual equivalent is Dreadsexual (aka: Guiltisexual)