My husband switched from android to iPhone finally and we didn’t know about family sharing so he used my Apple ID/ now he gets all my messages. How do I change or remove my Apple ID and invite him to create his own thru family sharing

Hello.

How to sign out Apple ID: go to settings > name surname > scroll down > sign out. Don't forget to turn off activation lock (settings > name surname > find my) that your husband could associate device with his Apple ID. Then create Apple ID and invite him to family (if it is not created, create it)

When changing to the new ID, there may be some data loss, but you can minimize it. If syncing photos with iCloud, ensure Optimization is turned off in Settings/Your Name/iCloud/Photos and/or in Photos/Preferences/iCloud. Then make sure full resolution photos are on the device/computer. When signing out of iCloud, if asked whether you want to retain data, choose yes. Messages conversations will be lost if they are addressed to the ID. See the article below for other places that the old ID should be removed. See Winston Churchill's response in the below discussion.

How to transfer all files from one iCloud account to another

 Apple ID email address or password - What to do after you change