__________ (Your name)
Date: __/__/____ (date)
I write this letter to express my heartfelt apologies for fighting with you. I know that it would be difficult for you to forgive me as I ____________ (cheated upon you/ lied/misbehaved/ any other). Moreover, I know that you know that my friends have been involved in all this argument and they were the reason that I argued with you as they made me feel ___________ (jealous/ insecure/ any other) about this relationship.
I miss you a lot. I miss your smile, the things that you have done for me. You have been with me during the darkest phase of my life. I messed up things and I regret not handling this situation maturely. I would literally apologize for the misdeed that I have done and request you to come back to my life and accept me as your partner.