Getting married with feelings for ex

I'll be 26 in January and I'm getting married in two weeks, on Christmas. However, I still have feelings for my ex. Our separation was mostly his fault, but I ended it and after two and half years he still has feelings for me. When he found out that I'm getting married he begged me to don't do that! I love my future husband so much, so I know I want to marry him. But what would you do?