There is another option, not topical here, called addiction to pornography. A basically decent fellow who loves his wife often takes on a fantasy life, which has other impacts on the marriage. Google "addiction to pornography" and you'll find this is epidemic.
"Honestly, I think women who want that approach should just tell their husbands go elsewhere but be discrete."
Yes, the French were especially good at this, especially when they still believed in marriage. Now that marriage is optional in France, there is no need to even be discreet anymore. There is no vow to break.
Unfortunately, the notion of having both a wife and a mistress is not culturally acceptable in the USA.
I agree, that culturally in the US its not acceptable, still happens, and yes many wives do know, and vice versa as well.
I don’t think pornography is going to keep someone from straying if they are getting nothing at home, purely because the other person isn’t interested. Might keep them from straying for a while, but self satisfaction doesn’t abate the desire to truly have sex with a partner who enjoys having sex with you.
As I’ve said, if the marriage is sexless, and the reason isn’t because of medical, or that both partners are asexual creatures, the one wanting sex will more often than not, EVENTUALLY find it elsewhere. I honestly think that in a situation where one partner is not remotely trying to satisfy the needs of the other, they really have no basis to complain when their partner finally does break down and go elsewhere.
Not advocating it, but being pragmatic.