It may also be called by other names such as infidelity, adultery or even cheating on the spouse.
While the wife may accept or even tolerate once in a while a hug or even a kiss with other woman but may threaten the sanctity of the existing relationship or marriage if it happens too often.
Recommended reading: How to save Marriage and Avoid Divorce This may sound a relatively strange reason but it is possible that some husbands have this desire to reward themselves when they achieve something to do self gratification or self congratulation through more sex with other woman.
This also gives a reassuring feeling of “being a man” to some men.
Please refer to: Mistakes Every Newlywed Couple Makes If caught or confronted, the logic usually given by such men is that just because someone is married does not mean that they can’t love someone else too.