What should she do? Who is right?

girl finds her dream wedding gown (LOVES the dress) But...then decides her fiance is not "the one" and calls off the wedding. Three years go by... As her new boyfriend and her begin talking about their new life together/getting married etc. He tells her he does not want her wearing THAT dress for their wedding. her view is, she spent major $ on the dress and still loves it and feels that the dress was purchased to wear when she married the man of her dreams which she now feels she has found. Friends have suggested she tell him she found a new one and then just wear the dress..... No one has seen the dress. But if he ever found out...it would not be good to start a marriage on that deception.