Asexuality is chiefly about noticing a distinction between the emotions you perceive in other people, and the emotions you perceive in yourself. We give a name to this distinction, for example by saying some people experience sexual attraction and some people do not. And we discuss appropriate responses to our emotions, for example by saying that some emotions mean we want to have sex, and other emotions do not.
Within ace communities, we often discuss further distinctions in emotions. Again, we give names to these distinctions, for example by talking about romantic attraction, platonic attraction, aesthetic attraction, sensual attraction, and so forth. And we discuss appropriate responses to these emotions, for example by describing what kinds of relationships might satisfy our emotions, or if a particular emotion only makes us want to look at a person.
The ability to distinguish different emotions is a nascent research topic in psychology. And while you shouldn’t let psychology research dictate how you live, looking into the research may give us insight into a common topic.