At the end of the day, it is your wedding. Because you are doing a destination wedding and going away and going to be spending time with your family and friends having her there would take that time away from spending time with the people you actually want to be spending time with. Having said that, you can kindly tell her exactly how you feel really. I am a big advocate in doing these things. You can write her a message on FB or an actual letter saying something along the lines of: I appreciate your kind thoughts on our upcoming nuptuals. I feel it is really important for me to spend time with the friends and family who have supported and encouraged me over the last (your age) years. It saddens me that you have not been there for monumental events in my life, and I have made peace with it, I would like to share my wedding with those who have celebrated with me me and encouraged me when times were tough. Thank you for understanding. (Maybe I am a little bit of a drama queen, but I feel that honesty is the best thing!) I had to do this for my step-grandmother. She was upset, and she stopped talking to me, which was no different than the way it was before, so status quo, and she knows how I feel.