I am a single mother who just married a millitary man.?

the father of my child has not been in her life for a 1 1/2. she is now 4. No custody agreement, he does not pay child support, and I have always kept medical insurance on her. My new husband wants to pcs to Germany, but I know I would have to go to court to get her father to sign the passport. Will this be a challenge for me? I know the father will fight out due to his mother. The father does not live in the same state as us and I honestly don't know where he is.