Dear (Name of person)
I hope my letter finds you in good health and good spirits. I would like you to know that I deeply regret past occurrences that have occurred between us. I am ashamed of allowing self-prejudices to come in the way of our friendship and consequentially affecting our families as well. A sense of mutual understanding in any relationship is paramount for our well-being. I now realize I was not sober enough to let both of us reach a level of understanding that would have prevented things from going as sour as they did. The realization of wrongdoing stems not only from me but my entire family for not having valued your position in society and as a family, a unit that needs to be highly appreciated and respected.
I believe this is the time for a change, and it is why I reach out to you to ask for your forgiveness regarding our ruined friendship. I now deeply understand the value of seeking more information and understanding from both sides before making any weighty and hasty decision that might lead to a whole friendship and family in ruins. This kind of bitterness has reaped me off an excellent friend I considered family, and unfortunately, I took so long to come to this realization. I can only understand how deeply you were hurt and how what happened might have affected other aspects of your life. It would be unfair of me to tell you to find forgiveness and let go, but I wish that you might seek this now and in your future endeavors. Rest assured, this will never happen again.
With love,
Yours affectionately
(Your name)