Password Sharing

Me and my long term boyfriend have set up Family Sharing. We each have our own Apple IDs but they are connected through Family Sharing. It has come to my attention today that in his passwords folder he has every single historic and current login of mine, things that were set up prior to us being together/haven’t used since being together. I’ve tried to search how I can revoke this but not a scooby. On the Family Sharing he is set as Organiser and I’m adult.

Something else to consider he recently started using my old iPad for work, logging out of my Apple ID and logging into his, could this be the problem?

If anyone knows how to undo this I would be very grateful.