Welcome back to the Wefugees Community and thank you for reaching out to us.
If you marry an EU citizen who is entitled to the "freedom of movement" according to EU law (as employee, for instance), you can apply for a residence permit card for family members of nationals of EU member states. Please see this website (here specifically for residents of Berlin) for a list of the requirements. The residency card is generally issued for five years and you are allowed to work as employee as well as to be self-employed.
If you need more information on the documents required for the marriage procedure in Germany, you may want to read our blog on this topic. A passport, birth certificate and a certificate of no impediment are among the standard documents. The civil marriage takes place at the so-called "Standesamt" (registry office) and the waiting period for a wedding appointment varies from place to place. I recommend you to contact a Standesamt (i.e. in the municipality where your partner lives) to get further counselling and information.
EU citizens entitled to the freedom of movement/EU and their family members are able to receive social benefits and support as well, in case their income can not cover the family's costs of living.
I hope this helps and please don't hesitate to get back to us with any further questions.
All the best,