Whose Life Is It

כחיצים ביד גבור כן בני הנעורים - Like arrows in the hand of the mighty, so are children.

Tehillim 127/4

A slightly edited poem I saw:

Your children are not your children. They are the sons and daughters of Hashem.
They come through you but not from you,
And though they are with you yet they belong not to you.
You may give them your love but not your thoughts,
For they have their own thoughts.
You may house their bodies but not their souls,
For their souls dwell in the house of tomorrow, which you cannot visit, not even in your dreams.
You may strive to be like them, but seek not to make them like you.
For life goes not backward nor tarries with yesterday.
You are the bows from which your children as living arrows are sent forth.
The Archer sees the mark upon the path of the infinite, and He bends you with His might that His arrows may go swift and far.
Let your bending in the Archer's hand be for gladness;
For even as He loves the arrow that flies, so He loves also the bow that is stable.

One can't live his children's life for them [as much as I sometimes see people trying]. All he can do is gently guide them, love them, teach them [primarily by personal example] and daven for them. The rest is in their and His hands.