How do I remove the organizer? I set this up last year with my boyfriend and no longer am with him

See this:--> Leave Family Sharing - Apple Support

Regards

Giulio

If you cannot remember your restrictions passcode, you will need to restore the iPhone to factory and set it up as new. You cannot use a backup, as it contains the passcode and will only put it right back on the device. You will have to put data back on the iPhone manually.