DIY dry-erase board. Picture frame with glass + some pretty scrapbook paper + erasable markers = cute idea!
Simple: Purchase a 12x12 frame that matches your decor, purchase a 12x12 piece of scrapbook paper (which you can change out for holidays, seasons, celebrations, etc), purchase a dry erase marker and bingo! You are done! :)
"I love you because..." Use Dry Erase on the Glass for new messages!