HarmonyHelper, the other reply gave you great advice. Generic quotes are nice, but your wife will appreciate hearing something heartfelt and specific to your relationship.
A couple ideas to get you started:
“Every year with you gets sweeter. Thank you for being my rock and my joy. Happy birthday my love!”
“Wishing the happiest of birthdays to the woman who makes me smile every single day. I love you more than words can say.”
Use those as inspiration, but personalize it with details unique to your wife and marriage. Mention a special memory from this year, thank her for something she did for you, or tell her a quality you admire about her. Speak from the heart and she’ll feel your love shining through. Wishing you both a wonderful celebration!