She wants to leave her stuff around to make you feel more like crap & have the upper hand. Play with your emotions, as she's beaching it.
Its time to show this cheating fiancée that she no longer has you pegged.
If you can't get her to get it soon, then at least get it out of your sight.
All this is prolonging starting the no contact process.
Stuff is just stuff. Your peace of mind & healing is the priority.