«O, call not me to justify the wrong
That thy unkindness lays upon my heart».
Regressing to his former melodramatic verse, the poet begs the woman to be honest with him and confess her infidelity.
O, call not me to justify the wrong
Coming as it does directly after the previous sonnet, in which the poet appears to have mastered his insecurities, the poet’s sense of abandonment in Sonnet 139 is surprising. However, recalling his apparent helplessness in standing up to the young man’s transgressions in earlier sonnets, the poet’s response to the woman’s continuing infidelity is expected.
Although weary of making excuses for the woman’s wantonness, the poet’s rationalizations persist. As long as the woman gives the poet her full attention when they are together, he will excuse her actions when they are apart: “Tell me thou lov’st elsewhere; but in my sight, / Dear heart, forbear to glance thine eye aside.” Plainly the poet still loves her; however, she humiliates him with her open flirtations. As with the youth, the poet allows the woman to dictate the terms of the relationship. Note the many phrases in which he begs the woman to act because he is unable to: “Wound me,” “Use power with power and slay me,” “Let me excuse thee,” “Kill me,” and “rid my pain.” Unable to act resolutely, the poet begs the woman to dispatch him swiftly.
English audio from YouTube Channel Socratica
Summary from Cliffsnotes.com