A man who has affairs isn’t a man.
A woman who won’t have sex with her husband isn’t a woman.
A man who doesn’t make an effort to make sure sex is a two way satisfaction agreement isn’t a man either.
But, yeah. A woman refusing to have sex with their husband for a year is a woman holding her husband’s head underwater and wondering why he’s acting so crazy.
The one thing a woman controls is the “sweet thing”. If she holds it back, she loses almost all her leverage with the husband. The promise of sex keeps a man engaged. If she loses that, she finds that he disengages. Pretty soon, he is spending more time “with the guys”. beach trips, hunting trips, etc.
I know because guys talk about it. On a trip, someone will ask “Did your wife give you any resistance?” “What’s she going to do? Stop having sex with me? HAHAHA”. Laughs all around.
If he is getting sex regularly, he doesn’t want to jeopardize that. It weighs on his mind as he makes decisions.
Having an affair is a nightmare unless she doesn’t care. Then it is still a nightmare because any woman they would have an affair with a married man is crazy. And crazy ain’t never worth it.
Think of marriage as (in part) a contract to be the sole-source supplier of sex.
In the business world, any sole source supplier contract will contain a clause that the suppliers must make their best effort to supply the quantity desired, and that refusal to do so makes the arrangement void, and frees the other party to find another supplier.