Even today, we rarely socialize with co-workers of the opposite sex.  Back in July, the New York Times documented, then analyzed, this gender divide:

Men and women still don’t seem to have figured out how to work or socialize together. For many, according to a new Morning Consult poll conducted for The New York Times, it is better simply to avoid each other.

men and women are wary of a range of one-on-one situations, the poll
found. Around a quarter think private work meetings with colleagues of
the opposite sex are inappropriate. Nearly two-thirds say people should
take extra caution around members of the opposite sex at work. A
majority of women, and nearly half of men, say it’s unacceptable to have
dinner or drinks alone with someone of the opposite sex other than
their spouse.

What are the underlying motives?

[P]eople described a cultural divide. Some said their social lives and
careers depended on such solo meetings. Others described caution around
people of the opposite sex, and some depicted the workplace as a fraught
atmosphere in which they feared harassment, or being accused of it.

This is all supposed to be terrible:

One reason women stall professionally, research shows, is that people have a tendency to hire, promote and mentor people like themselves.
When men avoid solo interactions with women — a catch-up lunch or late
night finishing a project — it puts women at a disadvantage.


“Organizations are so concerned with their legal liabilities, but
nobody’s really focused on how to reduce harassment and at the same time
teach men and women to have working relationships with the opposite
sex,” said Kim Elsesser, author of “Sex and the Office: Women, Men and
the Sex Partition That’s Dividing the Workplace.”

The article is almost over, however, before it discusses the most obvious rationale for these norms:

People who follow the practice in their social lives described separate
spheres after couplehood. They said they wanted to safeguard against
impropriety — or the appearance of it — and to respect marriage and, in
some cases, Christian values. That often meant limiting opposite-sex
adult friendships to their friends’ spouses.

And the piece never mentions who benefits most from these norms: husbands, wives, boyfriends, and girlfriends of the people who follow them!  It’s hard to imagine that these rules don’t reduce the prevalence of adultery and cheating.  And even if they didn’t, the rules still provide reassurance and a sense of security for these Forgotten Men and Forgotten Women.  Any considerate partner will take such feelings into account.

The world is full of trade-offs.  If you make cross-gender relationships more comfortable at work, you also make them less comfortable at home.  And as my Rotten Spouse Theorem emphasizes, you should expect anything that brings disharmony to your relationship to ultimately harm your entire family:

Of course, it’s conceivable that you can hurt your spouse without
hurting your children.  But probabilistically, you have to expect your
family members’ pain to move in unison.  Think general equilibrium:
The way you treat your spouse ripples out to your children.  The way
you treat your spouse affects the way your spouse treats you, which
ripples out to your children.  The direct effects are more visible, but
that doesn’t make them more real.  A good parent must, as Bastiat says, foresee the indirect effects of his behavior with the “inner eye of the mind.”

If you’re abnormally high in self-discipline and your partner is abnormally low in jealousy, the NYT critique of current workplace norms is understandable.  But not every couple is like that.  In fact, they’re a rare breed indeed.