Can i enter a house if the lease is still in my name?

me and my ex fiancee where renting a house and we separated and i moved out me and her are still on the lease and she is refusing to give me all my stuff i have a receipt for the 52 inch flat screen and some other stuff im going to ask my landlord for another key and just go there when she isn't there and take all my stuff but first i wanted to make sure i cant get into trouble for it as i said im still on the lease and im only taking things that belong to me i just don't know if im aloud to go in and take it or not i live in washington state if that helps give a better answer thank you