The same could be said about the wife. If shes not fulfilling her duties in the bedroom, then the husband will cheat and get a new pussy.Most women who cheat do so because their husband isn't fulfilling his responsibilities as a partner. They can't get their needs met at home...so they look elsewhere. Ofc there are also some women who just straight up want new dck, even if their husband is the best possible, but I don't think that's as common.
Men are sexual creatures and women need to know how to entertain and keep them occupied. Even if that means trying new things. Women/wives should read sex books, watch porn videos and learn from it, so they experiment with their husbands.
If the man is happy in the bedroom, then it increases his ego and motivates him to become a better husband. Better husband = happy wife = Good and healthy lasting marriage.