A little over 5 years ago, I met my ex-husband. I was 6-months pregnant with my now 5-year-old daughter. He now wants custody of my child even though she has lived with me since birth. He is on her birth certificate as the biological father and wants to be in her life. Can I file a paternity action against my ex-husband to establish that he is not the father of my daughter in order for me to retain sole custody? \
Since your ex-husband is listed as the biological father on your daughter’s birth certificate, he does have a right to assert his parental right to custody. Depending on your state family law code, you may be able to file a paternity action against him to prove that he is not the father and have his parental rights terminated.
Nevertheless, there are some states that have laws that permit non-biological fathers to retain custody of children born during the marriage. You should consult with a family law attorney to find out if such laws are applicable in your state.