"Sonnet 110" might be labeled as a confession poem. In it the speaker admits to or confesses having loved people other than the young man. However, the more important point that the poem makes is that the speaker pledges to be true to the young man forever after. The speaker vows to be constant.
This sonnet also has a structure with the division coming between the octet and the sestet. In the octet, the speaker reflects on his experiences or experiments with love in the past. In the sestet, the speaker pledges his fidelity in the present and for the future.
In the first quatrain, the speaker admits to having acted like a fool. The word motley (in line 2) refers a multi-colored costume worn by a court jester or a clown. The speaker is declaring that his actions in loving others have been foolish. The speaker also admits that in loving others, he has "gored" or wounded his "own thoughts" (line 3). The speaker means that he has acted against his own better judgment and his own reason. He had allowed his passions to become stronger than his mind (the reason versus emotion conflict). In other words, the speaker now regrets those actions. He additionally admits or confesses that in loving others, he has sold his love cheaply (also in line 3). The word dear means precious or valuable. So, "what is most dear" is his love. By saying that he gave his love away