Custody battle

TT

I have a 15 month old son who has been in my care since he was born. Last year my boyfriend (not my sons father) took on the roll of dad when my son was just 7 weeks old. It wasn’t till my son was five months old that paternity was established. His biological father has only seen him 5 times for a total of 10 hours. Back in June my sons biological father was arrested for criminal tampering and having 3 ounces of marijuana on his person. He texted me July 2nd the day before my sons birthday wanting me to tell my son he wished him a happy birthday. (I did not) He then waited till October 2nd to text me asking me to see his son again (3 months no contact, even seen me in person) I won’t allow my son to see his father due to the recent arrest and my boyfriend wants nothing more than to adopt my son. I’m afraid of losing my baby since his biological father stated he didn’t want anything to do with my son. What can I do?