This is the story of the second fray, a word that means to cause deterioriation or wear on something, usually material, by rubbing it. Metaphorically, this can apply to less tangible things, such as our nerves or our tempers.
This fray is closely related to the word friction, as both have as a common ancestor the Latin fricāre, meaning “to rub.” It makes sense—given enough friction, things will begin to fray. But language isn’t always so neat. One early sense of fray that existed in the 1400s, but which has since fallen out of use, meant “to bruise” (as in, with our strokes we shall fray him). In a translation of Ovid’s Metamorphoses dating from the 1500s, this very same sense in a different context is used to mean “deflower” (deprive of virginity). Can we connect the dots from rub to bruise to deflower? Therein lies the rub.