Hello,
You know about my life, my frustrations, my emptiness, and you probably know that I've really grown to love you. I felt it from the day I first met you. I constantly think about you in a fantasy world thinking about 'what if' scenarios that would allow us to be together in a relationship, however I know that this is impossible for several reasons, but I still hang on to the thoughts which has let me to a point of an emotional affair with you. This has without doubt caused strain in my marriage. I have become distant, unloving, and have all but given up. This has shed light on things which I know I must deal with, and the outcome is uncertain, but I have to think that after almost 30 years with my wife, I can salvage this relationship and ultimately make it better.

What this means for us though is that I have to end our friendship, and must stop spending time with you. Talking, texting, having lunch, going out for drinks, etc.. Every moment I spend with you puts my marriage in jeopardy. It pains me to do this, but I must. I sincerely hope you find what you're looking for in this life, and wish you all the best.