"why monogamy matters"

Yes,monogamy matters.It is seen in research studies that people who opt for causal sex are more likely to develop depression especially females.Monogamy provides a stability in a relationship that is absent in a causal sex I am not stating that all premarital sex leads to emotional downfall and unsteady relationships but individuals that get to know and care each other before sex,have a much better outcome.This is the basic reason that monogamy results in much more lasting and satisfied relationship then one outside of marriage and of causal sex. I feel that it is much healthier for oneself to actually  wait for someone that one actually cares.