Remember! Adultery is one of major sin in Islam.
No one is promoting adultery and fornication at all. Polygamy is the subject at hand.Because their lack of imaan simple as that.
If you are lusting for another woman it is because first you didn’t lower your gaze and you have too much time to look around instead of enjoying time with your wife and kids and secondly this filthy western society promote nakedness and pornography so women are walking around half-naked...
Fear Allah don't fall in adultery because you are not only betraying yourself, your wife, but also your kids and your whole community.
If you feel sexual desire toward another woman, make duas to Allah so that he makes it
disappear, Fast until those desires disappear and at last resort talk with your wife that you want to marry another woman but bear in mind all the responsibility which come with a second wife.
Life is short guys don't fall astray.