Jeff Atwood, father of 1, soon to be father of 3, wrote a great article on parenthood, which I highly recommend, if you are so inclined.
As an adult, you may think you’ve roughly mapped the continent of love and relationships. You’ve loved your parents, a few of your friends, eventually a significant other. You have some tentative cartography to work with from your explorations. You form ideas about what love is, its borders and boundaries. Then you have a child, look up to the sky, and suddenly understand that those bright dots in the sky are whole other galaxies.