[Dr. Sivana]

This really isn’t about “couples,” as in married couples or even cohabiting couples, because “couples,” such as my husband and me, are already in the same environment, infection-wise.

The unexcerpted version of the article states otherwise:

The study also mentions that having sex with people who are together in quarantine is safer, but there is still a risk. For instance, if one partner goes outside to run an errand and is exposed to the virus, they can transmit it to the other.

[Tax-chick]

If people are living together, they’ll pick up germs from one another in ordinary daily activity, unless they wear plastic-wrap suits all the time.