Due to the many willy unknowns and willy fears, we still need to define things like preferences. These terms are currently shifting or even disappearing.
The term heterosexual, like homosexual, was coined around 1869. Heterosexual was more the term for someone who was “oversexed” at the time. Too busy with sex. Note the year, diseases such as syphilis were rampant and there were no antibiotics yet. Victorian principles were needed and sexuality was better limited to the bare essentials. However, heterosexual in origin does not mean a preference for the opposite sex, but more the urge to want to do it with a woman every time while jerking was much better for overall public health.
Homosexuality is also a relatively modern term, just like bisexuality. In the gay world, moreover, only in the last 20 years have words like “bottom” or “top”, also known as “active” or “passive”, become popular.
There are also definitions that are never used. For example, one could safely call almost every man an auto-homosexual. In his life he starts with himself. Can’t get enough of it at the time. And happily continues for the rest of his life.
In the time in which we now live, all boxes are slowly fading and disappearing.