Paradox in Sonnet 116?

Let me not to the marriage of true minds
Admit impediments. Love is not love
Which alters when it alteration finds,
Or bends with the remover to remove:
O no! it is an ever-fixed mark
That looks on tempests and is never shaken;
It is the star to every wandering bark,
Whose worth's unknown, although his height be taken.
Love's not Time's fool, though rosy lips and cheeks
Within his bending sickle's compass come:
Love alters not with his brief hours and weeks,
But bears it out even to the edge of doom.
If this be error and upon me proved,
I never writ, nor no man ever loved.

How could I talk about how Shakespeare uses Paradox in the Sonnet to create effect?
For the last 2 lines and love itself.

Any comments appreciated!

Weell, the first line itself 'let me not...' starts off negatively which would have gone against the conventions of love sonnets at the time, which may surprise the reader? Also there may be paradox in the way that Shakespeare addresses this to a man, yet brings up the idea of 'marriage' which may contrast with beliefs at that time..? Sorry if these points are a bit rubbish, i tried!