Analysis of I Know I Have Been Happiest

I know I have been happiest at your side;
But what is done, is done, and all's to be.
And small the good, to linger dolefully-
Gayly it lived, and gallantly it died.
I will not make you songs of hearts denied,
And you, being man, would have no tears of me,
And should I offer you fidelity,
You'd be, I think, a little terrified.

Yet this the need of woman, this her curse:
To range her little gifts, and give, and give,
Because the throb of giving's sweet to bear.
To you, who never begged me vows or verse,
My gift shall be my absence, while I live;
But after that, my dear, I cannot swear.