Today is your wedding day. Today, therefore, is the day when you must tell your beloved that you have been dead for over nine hundred years. You can only hope that love is enough to overcome your unusual condition.
Thoughts on planning your story: There are many ways you could interpret this prompt. Three that come to mind are ghost, zombie, and time traveller. Your initial interpretation of the prompt can take this starter into many different directions and vastly different genres. Have fun with it.