Love between a husband and his wife teaches children to love those of the opposite sex. It teaches children to have an inclusive “us” view of the opposite sex instead of an “us vs them” “battle of the sexes” worldview. Homosexuals have all male “gay” bars, but heterosexuals believe that a man and woman should unite together in love.
When Jesus (God in the flesh) was asked about marriage, he took us back to the original and true meaning of marriage which is one man and one woman joined together by God’s blessing to become one flesh. And this love between husband and wife, this “one flesh” love, becomes so real that typically nine months later it’s given a name.
He [Jesus] answered, “Have you not read that he who made them from the beginning made them male and female, and said, `For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh’? So they are no longer two but one flesh. What therefore God has joined together, let not man put asunder.” - Matthew 19:4-6