This poem is based on much Italian sixteenth-century poetry in which the poet carries the worship of his beloved to extreme lengths and lamenting the woman's callous and cruel treatment. Wyatt's version, however, flips this theme on its side in order to draw the lady in. If you think Wyatt is protesting to much, you're right.
In summary, Wyatt tells the difficult lady that she can love whomever she wants because he simply doesn't care; he tells her to do and to think whatever she wants because, as far as he's concerned, he doesn't care who she loves or who she hates. In a typical Wyatt stance, the poet says that he "dotes not" on her love, that is, he doesn't care whether she loves him or not, and he wants her to keep in mind that he doesn't care what she does.
In poetic terms, this is called a conceit--in this case, by telling the lady repeatedly how little he cares about her love, she is supposed to understand he is absolutely unstrung without her love.