ive had to set up a new apple id as my ex partner keeps going into all my stuff and changing it but now wont let me use my apple music as saying signed in for 46 days on a different account , but ive deleted everything ???

Sounds like you've already associated the device/computer to an account, deleting everything won't make any difference to that : View and remove your associated devices in iTunes - Apple Support

You can either wait until the 90 days have completed, or try contacting iTunes Support and see if they can remove the association so that you can start an association to a different account : http://www.apple.com/support/itunes/ww or https://www.apple.com/emea/support/itunes/contact.html

Try doing a name change and a password change on your original account. That should allow you to keep what you have, but remove the ability of your ex to interfere.

Apple ID Name Change

Apple ID Password Change

What to do after you change your Apple ID or password - Apple Support I suggest doing this before you change your Apple ID or password.