If she was talking to this guy before breaking up with you, she broke up with you for him. Unfortunately she is the type of woman that can not break up with someone without having the next guy lined up (assumption).
If I were you I'd be pissed that she has left you the job of packing up her stuff. Do it but don't do it carefully. Chuck shit in boxes and get it out of your space. You don't need that in your face every day.
'People are never perfect but love can be. People waste time looking for the perfect lover rather than creating the perfect love' - Princess Leigh-Cheri from Still Life With Woodpecker.