How about I tell my fiance I wanted to end the phone call with her?
Why would you want to end the phone call with your fiance?
I want to listen to a music on my iPod.
It's understandable that you want to listen to music, however, it will be there later. You shouldn't end a conversation with your partner just to listen to music. You should find out first if there is anything your fiance wants to talk about.
It's her fault she should just be patient.
I'm not sure why, as a sensible person, you didn't consider the relevance of the two. Her conversation may include vital information that she wishes to share with you because you are her knight in shining armor. So don't cut her off because she loves you and music can't love you back.