Welcome to the Wefugees community and thank you for reaching out to the community!
Generally, if you get married with a German citizen or with someone holding a residence title in Germany, you can apply for family union in order to live with your spouse. You would then also be granted a residence permit. I'm unsure if there are any exceptions for people holding said "Aufenthaltskarte" (as it's already granted to her because of a family member), but technically, she has a residence title.
Here is some more information on that matter: https://service.berlin.de/dienstleistung/305289/en/
You can also have a look at our platform and search for "residence permit Germany" to have a look at similar cases.
I hope this helps for now. Please feel free to contact us again if you need any further assistance!
All the best,