Sure! Here’s a sweet way to start a birthday letter to your boyfriend:
My Dearest [Boyfriend’s Name],
Happy Birthday to the love of my life! On this special day, I want to remind you just how much you mean to me. You are my sunshine on the cloudiest days, and the thought of you brings a smile to my face, no matter what. Today, we celebrate not just the day you were born, but the incredible person you’ve become. I’m grateful for every moment we share!
Feel free to customize it to fit your style!