When was the first recorded instance of a heterosexual being aroused by a homosexual relationship between members of the opposite sex?

by alliteratorsalmanac

It would be interesting to know about this, in both the lesbian and gay possibilities for the scenario.

alliteratorsalmanac

Looks like my question is stupid and unpopular. If anyone searches through the archive later and finds this, I did some research myself and the oldest I could find online for lesbian erotica (probably) aimed at men is here.