And she is all of solid fire
And gems and gold, that none his hand
Dares stretch to touch her baby form,
Or wrap her in his swaddling-band.
But she comes to the man she loves,
If young or old, or rich or poor;
They soon drive out the Agèd Host,
A beggar at another's door.
He wanders weeping far away,
Until some other take him in;
Oft blind and age-bent, sore distrest,
Until he can a Maiden win.
And to allay his freezing age,
The poor man takes her in his arms;
The cottage fades before his sight,
The garden and its lovely charms.
According to the Oxford English Dictionary, the word allay means to lay down or to set aside. The man that this line is referring to in the poem is using the cycle to grow young again. Old men use young girls and old women use young boys in this poem to become young again. It’s a vicious cycle that is more vividly described in lines 12-14 when the first old woman is using the first young boy to become young again. He takes the young girl in his arms and the cycle continues. 

The Mental Traveller