Dear (Name),
Greetings from (city/state/country)! I sincerely hope that all is well with you and yours. I am fine. Surprisingly, I've been keeping myself quite busy since I last saw you. Which reminds me, the last time we were together I had a (ball/blast/great time), and you were so (charming/crazy/funny/hilarious) I couldn't get over it. In fact, I still haven't.
(Name), I think of you every day - I can't help myself! Memories of pleasant times with you are hard to suppress, and my being so far away from you doesn't help matters either because it makes me wish I could be with you even more. Truthfully, knowing that you are alive and I can't be with you is an unbearable torment.
(Name), when will I see you again? I can't stand the pain and anguish of our separation much longer. I yearn to gaze into your captivating eyes. I crave your tender touch, your warm embrace and your passionate kiss. I yearn for the day when I can be with you again.
Until that (fateful/wonderful) day arrives, I wish you the best life has to offer. (Name), please take good care of yourself and write me as soon as you can.
Love,
(Name)