Family sharing users get promo emails about my purchases

Unless they have your email address added to their devices, they should not be getting your promos.

What exactly do you mean when you say the "are in your family sharing account"?

Family Sharing uses separate accounts. If they are logged in to your Apple ID on their devices, then yes they would see your emails and promos, because it is the same account. They should all be using their own Apple ID on their own devices.

eiddor wrote:

Sorry, I should have been clearer - They each have their own Apple IDs and email accounts, but they are part of my Family Sharing Plan (iCloud+ is the only subscription that is shared.) They are each logged into their devices as themselves, and are receiving emails to their Apple ID email addresses.

Sounds like something is not exactly right. They should not be getting emails meant for you unless somehow your Apple ID is added to their devices. There is no way this is happening otherwise.

I would suggest you check on there devices what account is signed in in Settings ➜ Apple ID ➜ Media & Purchases, as well as verifying your email account is not added in Settings ➜ Mail ➜ Accounts.

You could always ask Apple:

Refer to this document for ways to contact Apple ➞ Choose your country or region - Official Apple Support

Select your country (also look for "other" regions), then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service by telephone ➞ Contact Apple for support and service - Apple Support

Is there actually anything linking these emails to your account? It may be Apple is just sending them promotional emails directly to them alone as people with Apple IDs (and therefore email addresses known to Apple) using a service. We don't work for Apple so we don't really know how they do things. I wonder if they are just getting these things incidentally as users of Apple Music even if only because you provide it to them? They can try unsubscribing from them.

--> Manage emails that you receive from Apple - Apple Support