Want to stop backing up and use it to store what I put on it

WD External Drives External Drives for PC
2

Looks like the iTunes library was moved to the external drive.

You can put the library in any location you wish. Please see the following article for more information:

http://wdc.custhelp.com/app/answers/detail/a_id/1393

The article applies for moving to an external drive but the same should apply to move to another location.