Many men follow what has come to be known as the Graham or Pence rule: Never be alone with a woman who is not your wife.
Evangelicals now mock this rule, but it remains a matter of common sense modesty that has served men well for millennia.
Ambrose of Milan, a fourth-century church father, explains [bracketed translational notes added]:
“If we are to preserve our modesty we must avoid… intercourse [i.e., habitual communications] with women…
There is no need for the younger clergy to go to the houses of widows or virgins, except for the sake of a definite visit [i.e., clearly defined in purpose], and in that case only with the elder clergy, that is, with the bishop, or, if the matter be somewhat important, with the priests [i.e., presbyters or elders].
Why should we give room to the world to revile? What need is there for those frequent visits to give ground for rumours? What if one of those women should by chance fall? Why shouldst thou undergo the reproach of another’s fall? How many even strong men have been led away by their passions? How many are there who have not indeed yielded to sin, but have given ground for suspicion?”
Ambrose, Selected Works and Letters, chapter XX, pages 15-16