How does that differ from asexuals?
This little chart helps distinguish the differences:
Primary vs Secondary Sexual Attraction Model
This hypothetical model of sexuality takes the position that sexual attraction and desire can each be subdivided into "primary" and "secondary" forms:
Primary Sexual Attraction: A sexual attraction to people based on instantly available information (such as their appearance or smell) which may or may not lead to arousal or sexual desire.
Secondary Sexual Attraction: A sexual attraction that develops over time based on a person's relationship and emotional connection with another person.
Primary Sexual Desire: The desire to engage in sexual activity for the purposes of personal pleasure whether physical, emotional, or both.
Secondary Sexual Desire: The desire to engage in sexual activity for the purposes other than personal pleasure, such as the happiness of the other person involved or the conception of children.
One of the strengths of this model is that it clearly distinguishes demisexuals from both sexuals and asexuals. Most sexuals in romantic relationships feel both primary and secondary sexual attraction. The term demisexual, under this model, tends to refer to people who experience only secondary sexual attraction; this attraction can result in primary sexual desire. Since asexuals experience neither primary nor secondary sexual attraction, they cannot experience primary sexual desire. However, since they can experience secondary sexual desire, this model accounts for the sexual behavior of some asexuals.
Primary Attraction?
Sexual:Yes
Demisexual:No
Asexual:No
Secondary Attraction?
Sexual: Yes
Demisexual: Yes
Asexual: No
Primary Desire?
Sexual: Yes
Demisexual: Yes
Asexual: No
Secondary Desire?
Sexual: Yes
Demisexual: Yes
Asexual: Yes