That depends on whether we're talking about your own music (ripped from CDs for example) or paid content from Apple. If it's the music you purchased from the iTunes store, then it's nearly impossible to transfer this as paid content is linked to one specific Apple ID.
As a workaround, you can try using home sharing. But that needs two devices and I'm suspecting that it's one single computer that you're talking about. See here:
https://support.apple.com/en-us/HT201085
Another option would be to change the details for your Apple ID to transfer the control of this account to your wife, but the music would still be linked to that (your) Apple ID and would only be available when signed in with that ID. See here:
https://www.lifewire.com/can-purchas...ccount-2438292