The monogamous ideas that have been passed down through the ages means that couple are obliged to only make love with each other until the end of their relationship. Yet the modern consensus agrees; why should a lady keep being intimate with her husband if she doesn't want to? (Playing devil's advocate here as I have my own opinions on the benefits of sex for women, specifically the benefits of orgasms).
Be honest - would you really enjoy having sex with your partner if she was not into it? Even though sometimes in marriage we do what we don't want to, a lot of men don't want to have sex with an unwilling partner so they don't force the issue.
But men still have needs, even an (incomprehensible to women) need for variety. That's why the sex industry exists. If a man has not left his wife, even though he sees escorts or his wife is no longer making love with him as often, it's because he still loves his wife or doesn't wish to disrupt the life they have built together. Good for him is what I say.
Below is something that was sent to me by a man with the interesting distinction that he does not have sexual intercourse with sex workers. This explains why and how he sees escorts.