When we're kids, we're the apple of our parent's eyes, they love us and give us everything we want and they keep us away from the harsh realities of life, lightening any load of responsibility we might need to carry. A child is the most selfish creature, from being a baby crying for milk etc..its all just about me, me, me. One's world is shaped for one's self.
Then you get married...the famous word 'compromise' has always been heard, but this article is not a warning against the burdens of compromise, but an understanding of why compromise is so important for society. People carry on in their child-like fashion of living for one's self, when married your space is divided, you have to now put up with inconvenience and vice versa. You suddenly find yourself sacrificing precious time to spend with inlaws when you could think of a hundred better things to do. You find yourself doing stuff you don't want to, to make your partner happy, just like a mother who drags herself to get ready even though she's tired and take her little one to the playgroup because she knows it will make her child happy. Self-sacrifice for another person's sake humbles some of those frivolous characteristics of arrogance, selfishness, self-absorbed states of mind and it heightens the characteristics of mercy, love and selflessness.
Having kids only makes these feelings of mercy, love and selflessness stronger because that requires a lot more self sacrifice than marriage itself. But the beauty of having children, is that this self -sacrifice is shared by both parties for the same objectives, the happiness of the kids and hence the couple become stronger as they struggle together but share the same moments of joy.
So why are these humble characteristics important for society as a whole. Well, if everyone continued on a path of only thinking about one's self, we would forsake the useless - parents, grandparent, we would not care for the old, or for the environment, we would think short-term hence more promiscuity, adultery as we don't care for others and we just keep striving for what we need and want, we would con more people to get our way and we would easily spiral into depression if we couldn't get what we want. We just wouldn't have an appreciation for the bigger picture.
Of course this is all relative, this is not to say that EVERY one who doesn't get married has these traits, its just easier to avoid these traits by being married and having kids. But obviously this only happens if one co-operates in the marriage as a whole, not treating this union as a joke but something serious that he/she wants to make successful.
Marriage is not a fairy tale extension of romance, its a journey on which two people become best friends as they travel down the difficult path of bettering their personalities.