My Dear Friend: Of course it is possible to begin clearing karmic relationships in the life in which the karmic insult occurs. In fact, the first step is experiencing genuine remorse for one's actions. The next step is to ask for the other person's forgiveness. I know this can be a difficult step, since (depending on the act for which one has remorse) doing so can expose one to potential rejection, and rejection is particularly painful when one is asking for forgiveness. However, expressing one's remorse to the injured person is important - not so much for the other person as for the purification of oneself. In so doing, often one gets a powerful opportunity to confront internal "demons," or powerful levels of resistance, both of which can be significant teachers.

It is the heart coming open to change that actually cleans up the karma. Often, hearts open by literally breaking open. When remorse is genuine enough to crack open the heart, real healing begins. As the heart opens, one's creative capacity opens; and in truth, even though everyone makes mistakes and has experiences they later regret, still everyone has an infinite capacity for creating goodness, as well. It is important to celebrate the fact that no matter how many mistakes one has made; and no matter the gravity of those mistakes, one still retains a tremendous capacity for generating kindness, compassion and goodness. Indeed, if one forgets this very important point, then it does become impossible to "find any measure of peace or self-forgiveness in this life," as you so eloquently put it in your question above.

If one really chooses to clear karma in the life where it arises, it is necessary to go even deeper. Remorse, left to the devices of the ego mind, can lead one into depression, hopelessness, or other even more morbid mental state. This is why the mind must be transcended. It thus becomes necessary to enter into some mental purification with regard to the person one has injured. Perhaps you imagine this person as a Buddha, or a Christ, and you see yourself bowing or doing prostrations to her/him. Mentally, try to experience profound gratitude for their presence in your life, for it has been through the unfolding of the course of events that you have received a great lesson. You have seen something about yourself (or what you perceive as "your self") that you may not have seen had this person been absent from your experiential realm. What a gift his/her presence was to you - even though you have remorse about the turn of events. Hypothetically speaking, if another person shows up in your life and opens himself/herself to pain and injury so that you may become awake to the power of your thoughts, words and actions, what greater gift could that "other" offer to your enlightenment?

Of course, one cannot simply assume that the other person consciously remembers agreeing to serve in such a capacity. Indeed, it is always important to compassionately attune to the particular pain the other experiences, for such seeing begets true remorse and ultimately, compassion for both self and other. However, it is also important not to let the remorse (which is desirable) deteriorate into guilt (which is not desirable), for guilt often dissolves into paralysis, which is helpful neither to self nor the other person. What is helpful to both parties is compassionate understanding of the tremendous prices people pay to obtain their respective learning. It is ultimately through these often painful, seemingly demeaning, learning experiences that one gets her/his greatest growth. The Soul, you see, is willing to pay nearly any price to have its liberation.

Celebrate your learning, and celebrate the fact that others come into your life to facilitate that learning, whether consciously or unconsciously. It is indeed powerful to recognize that another human being loves you enough to take whatever karmic abuse the "lower self" dishes out in order that you might have your liberation from old karmic patterns. We must be careful not to wax "glib" here, for such gifts from others come with a significant price for them, as well. Rather, one must always be sensitively aware that all beings everywhere are paying heavy prices to obtain their learning - the learning that will ultimately free each from the suffering levels to which all have (and must) pay their dues.

I encourage you to delve deeply into the waters of reconciliation and redemption. Such is the work you came to do, and it will produce the spiritual maturity you seek. Do not wait for another life to dawn to clean up those karmic debts. Rather, use every opportunity you are afforded in this precious life to cut through the limitations of the ego mind, allowing transcendence to be the mark of your presence here on Earth. Apply yourself diligently to the task at hand, and rest in the assurance that like others before you, you too shall have your enlightenment. Walk gently upon the Earth, and dare to love all beings - that includes yourself!