Analysis of His covenant or protestation to julia

Why dost thou wound and break my heart,
As if we should for ever part?
Hast thou not heard an oath from me,
After a day, or two, or three,
I would come back and live with thee?
Take, if thou dost distrust that vow,
This second protestation now:--
Upon thy cheek that spangled tear,
Which sits as dew of roses there,
That tear shall scarce be dried before
I'll kiss the threshold of thy door;
Then weep not, Sweet, but thus much know,--
I'm half returned before I go.