XBox without s how can you see who is logged in (activities)?

I have a question, how can you see who is logged in via Xbox one s and what they are doing. Every time I watch Netflix or play games my ex boyfriend knows what I'm doing. He reportedly receives a notification. How can you switch something off?

You need to remove it from your account as a friend.

I don't have him as a friend

It must be linked to your account in some form. As a friend, follower, via mixer, …

You have to find out and remove or block it