BAH/Finances for Child Out of Wedlock

I was advised to post here for inquiry about the process for children born out of wedlock/what process needs to happen if marriage is not on the table. The father refuses to do any research or provide any other option than requesting myself do 51/49 custody. So, I’m trying to figure out options.

Enlisted (E-3) Marine (father) and civilian mother (myself) are expecting a child soon. The child’s father has given me an “option” to sign over or attempt to get documentation for him to have 51% custody, and myself, as the mother get 49% custody, which is absurd, and I am not agreeing to this, for numerous reasons. He advises if I do not choose this option, there is nothing he can do financially to support his child, and I am making it harder on him.

He believes if this custody arrangement is given, he will be able to obtain BAH and move out of the barracks for a place to live. This seems fraudulent to me, so, I really want to know financially and truthfully what options he has, and we have for the child and what the legitimate process may look like.

Any advice welcome. TIA.