Analysis of And love has changed to kindliness

When love has changed to kindliness --
Oh, love, our hungry lips, that press
So tight that Time's an old god's dream
Nodding in heaven, and whisper stuff
Seven million years were not enough
To think on after, make it seem
Less than the breath of children playing,
A blasphemy scarce worth the saying,
A sorry jest, "When love has grown
To kindliness -- to kindliness!" . . .
And yet -- the best that either's known
Will change, and wither, and be less,
At last, than comfort, or its own
Remembrance. And when some caress
Tendered in habit (once a flame
All heaven sang out to) wakes the shame
Unworded, in the steady eyes
We'll have, -- that day, what shall we do?
Being so noble, kill the two
Who've reached their second-best? Being wise,
Break cleanly off, and get away.
Follow down other windier skies
New lures, alone? Or shall we stay,
Since this is all we've known, content
In the lean twilight of such day,
And not remember, not lament?
That time when all is over, and
Hand never flinches, brushing hand;
And blood lies quiet, for all you're near;
And it's but spoken words we hear,
Where trumpets sang; when the mere skies
Are stranger and nobler than your eyes;
And flesh is flesh, was flame before;
And infinite hungers leap no more
In the chance swaying of your dress;
And love has changed to kindliness.