I wonder, by my troth, what thou and I
Did, till we loved? Were we not weaned till then?
But sucked on country pleasures, childishly?
Or snorted we in the Seven Sleepers' den?
'Twas so; but this, all pleasures fancies be.
If ever any beauty I did see,
Which I desired, and got, 'twas but a dream of thee.
And now good-morrow to our waking souls,
Which watch not one another out of fear;
For love, all love of other sights controls,
And makes one little room an everywhere.
Let sea-discoverers to new worlds have gone,
Let maps to other, worlds on worlds have shown,
This is a complex idea expressed concisely. Donne is saying that love dominates their lives and impacts on everything they see. So they interpret their world  through their own special lens of love.
The Good Morrow