Is the reason why he is cheating simply a biological normalcy? Is it right for humans to be in a monogamous relationship? Do we already unnofficially participate in plural relationships? Are you married with a husband who has a mistress and a girlfriend that you pretend not to know exist?

Less and less people are marrying these days and having families. We used to marry for socioeconomic status and for the need of children to help with the farm but now in our technical age we are marrying more for love. However, is that really working? But then if monogamy is not what's natural for humans then why do we have territorial tendancies such as jealousy?