Dear Blessing Jonathan,
Welcome to the Wefugees Community and thank you for reaching out to us.
It is a bit difficult to give tailored advice without knowing your situation in detail. Please also note that we are no lawyers and can not provide profound legal counselling. Based on the information you share, you may not be able to obtain an independent residence permit related to your marriage with a German citizen as you don't seem to have lived together as married couple for minimum three years. Whether it is possible to receive a residence permit as father of a child in Germany depends on several factors. If your child is German, you may be able to receive a residence permit according to section 28 of the German Residence Act (similar to your current residence permit). If your child is a third country national (non-EU), for instance, it may be a bit more complicated. Please see this thread for more information on this.
In any case, I highly recommend you to get some individual counselling in a migration counselling office or by a lawyer.
I hope this helps and all the best,
Meike