What are the arguments Donne uses to lessen the impact of the characters temporary separation?
This is such a great poem! You have a wonderful answer, but in addition to this, Donne uses the metaphysical conceit (an extended metaphor between two extremely unalike items) to lessen the blow of separation as well. There are two metaphysical conceits in the poem. The first is their love compared to a compass. He tells his wife that their love will not weaken because she is the fixed/pointed foot of the compass who leans toward him as he leaves the home...they are always connected through their spirits and minds. Their love is stronger than just the physical (hands and lips and eyes to miss) as others base their love upon. He tells her that she completes him with the circle they make and when he returns home, they are again together and erect as the two ends of a compass are after drawing the circle on a piece of paper. I always like to point out that the circle is the perfect shape...the shape of the wedding ring...there is no beginning or end, and where he begins, she ends...they are one, always, no matter the distance between them.
The other metaphysical conceit in the poem is the "gold to airy thinness beat". He says they are like gold...a malleable metal...that gold will never break no matter how much you beat it. It only gets thinner and spreads out. Their love is like this gold...they will never break apart, only spread apart the farther he travels. Gold is also a popular choice for wedding rings.