Apple Music family sharing concerns

I deleted my Pandora account because their program is glitchy and lacks features - even basic ones like being able to go backwards in autoplay mode. So, I switched to the Apple Music family subscription. I discovered that I have to have members be a part of my family, whereas with the other streaming services you can simply email an invitation, which is so, so much better.

I want to share my Apple Music with my girlfriend, her daughter, and my mom. My girlfriend and her daughter are already in their own Apple Family. They would have to switch to my family in order to use Apple Music. My understanding is once that switch is made, they cannot join another family (including their own), which is absolutely ridiculous. What happens in the event that we break up and I remove her from my family? She will not be part of a family anymore til 1 year after she was added to it, then her and her daughter can be in their own family again?

What other issues might we experience with switching families?

This is so frustrating and confusing whereas it is totally the opposite and awesome with the other streaming services that let you email an invitation link to anyone.

[Edited by Moderator]