So shall I live, supposing thou art true,
Like a deceived husband; so love's face
May still seem love to me, though altered new;
Thy looks with me, thy heart in other place:
For there can live no hatred in thine eye,
Therefore in that I cannot know thy change.
In many's looks, the false heart's history
“Thy looks” refers to the love that he still sees in the young man, but he suspects the boy’s feelings are “in other place”. 
 This line comprises two concise related clauses, syntactically similar, one balancing the other, an example of  syntactic parallel .
Sonnet 93