The whole world debates on this double standard about why it’s acceptable for male to be promiscuous but woman are expected to be monogamous. The whole feminist culture has came out to same concept. Why women can’t be and act same as men. Why it’s NOT ok for women to go clubbing and flirt with other men when they are married when it’s common for men. 

I can’t possibly convince anyone or change their opinion about this with some argument. People have their own belief system, culture, surroundings, social circle which formulates what they believe over longer period of time.

For me it’s more about natural behaviors and social roles of men and women. For men sex is mostly physical act. They can involve in sexual act with women who they just meet for five minutes or with someone who they have never thought about before . They can have sex and never think about that same women ever again. They can easily stay emotionally detached with women they have involved in sexual activity in regularly basics too. In other word , emotional relation and sexual relations are separate for men. Women are exactly opposite of that. If they involve in sexual relationship they are emotionally involved . It’s same biological nature in many animals too. Because of that throughout history family men being promiscuous has not been too damaging to family and society vs married women being promiscuous. 

Not saying every men has to have promiscuous relationship or promoting that in any way. But it’s in men’s nature and biology to be promiscuous. And he shouldn’t be seen as evil or criminal just because of that.