Sonnet 109 begins a sequence of apologetic sonnets using the image of travel as a metaphor for the poet's reduction of the attention he gives to the young man. He defends his absence against charges of infidelity and indifference. Beneath his apologetic manner, one detects an assertion of independence from the youth's control: "O, never say that I was false of heart, / Though absence seemed my flame to qualify." In other words, although the poet's love for the youth never lessened, he would have been justified if it had.
Three times the poet declares that no matter where he may travel — both physically and in his thoughts — he will always return to the youth, for the young man is his alter ego. This theme of unity, which was a dominant theme in earlier sonnets, including the phrase "thou mine, I thine" from the previous sonnet, is expressed in the phrases "my soul, which in thy breast doth lie," "That is my home of love," and "thou art my all." However, these sentiments seem more like responses to criticism of the poet's having traveled away from the young man than they do sincere, impromptu declarations of affection.