How do I remove ex-boyfriend and his partner from my iCloud after they synced devices and changed passwords?

The man that was living with me, a boyfriend decided to leave and so I had him removed from my iCloud, which I should’ve never shared in the first place with him. I found that out now, but since he has gone back home to his partner, they have both been in my iCloud and somehow they have synced my android my iPhone and my iPad and they have changed my passwords on everything on the daily for seven months and I am really I’m on the edge of breakdown. I need someone help me please from Apple.

[Re-Titled by Moderator]