Here you will find the Poem O Do Not Love Too Long of poet William Butler Yeats
SWEETHEART, do not love too long: I loved long and long, And grew to be out of fashion Like an old song. All through the years of our youth Neither could have known Their own thought from the other's, We were so much at one. But O, in a minute she changed -- O do not love too long, Or you will grow out of fashion Like an old song.