They usually have a preoccupation with spirituality, philosophy, and religion. I believe that what's happening with these people is that they are spending so much of their time in altered states that their consciousness isn't available to the sexual ones. Its already engaged with states that rule it out. Probably there are many states of consciousness that inhibit sexual interest. Others seem to invoke it.
Altered states are almost always either positive or negative.
The positive ones range from a mild mania to total bliss. Fear is the most common emotion in the negative ones, and can include anything from mild anxiety to stark terror. When a person is filled with a sense of well-being, a lack of sex won't won't make them feel that anything is wrong. For both types of people, there won't be any sense that sex is a real need. Others who are prone to altered states have a different pattern for both sexuality and their experiences of non-normal states.