Mere happiness is not the song I’m singing

Mere happiness is not the song I’m singing:
Of mothers’ joy a jagged piece is pain.
To love is to be amply burdened, bringing
Hearts with gifts to an uncharted plain.
Even so, one longs to be a mother,
Remembering a richness unreserved
‘Ere one could barely recognize another,
Sustained by love unsought and undeserved.
Deeper than oneself is one’s communion,
A revelation reached alone by union
Yet yearned for, though through years of love well served