Rent the Runway’s Jennifer Hyman has suddenly canceled her wedding to former Starwood executive Peter Mack just days before the lavish event in Aspen. Top entrepreneur Hyman — who co-founded the New York-based company with fellow Harvard grad Jenny Fleiss in 2009 and now rents out designer dresses to more than 1.5 million customers — was due to wed Mack in front of nearly 200 guests at the Moon Run Ranch in Old Snowmass on Saturday. Other events planned for the weekend included an after-party at the Caribou Club and a Sunday night concert by Edward Sharpe & The Magnetic Zeros. But according to an e-mail sent yesterday by Hyman to guests — all of whom had made expensive travel plans to arrive in time for the welcome dinner just three days away — “I wanted to share the very sad and devastating news that I’ve decided to postpone/call off my wedding this weekend in Aspen. There are a number of very important reasons that I intend to share with each of you personally . . . I am extremely saddened by this situation and it’s been incredibly hard for me to get to this point. But, I do believe that it is the right thing for me to do. I know that this news will come as a shock to most of you, which makes this even more painful.” She continued, “I know you have each made huge commitments of your time and money to come to Aspen this weekend, changed summer plans, made vacations out of it and I am so sorry — for everything. I feel horribly to have made this decision so last minute, to have had to make this decision at all and I hope that each of you can understand and support me through what I know will be a very difficult time in my life.” The move left stunned guests speculating why the famously organized fashion and media darling, who has dated Mack since 2010, would cancel at the last minute. “Jenn is not the type to call something this major off unless something dramatic happened. We just hope she is OK,” says a source. Her spokesman last night confirmed the wedding is postponed and asked us to respect the couple’s privacy.