[Your letterhead, if desired; if not, your return address]
[Date of letter-month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
After 15 years of being married, my heart still skips a beat when I think of you or hear your voice. Our love just grows deeper and stronger over the years as we keep stacking up the great memories of times we've shared. You grow more radiant over time, and I'm so incredibly blessed to be with you. Thank you for being just the way you are and for sharing your life with me. I am so excited to spend some special time with you on Valentine's Day-Happy Valentine's Day!
[Sender's first and last names]