My husband said he'd keep my son from me if we divorced.

My husband is emotionally abusive. We have had many problems throughout our relationship and have talked on more than one occasion about divorce. We had our first son back in November of last year, he is almost 4 months old. My husband told me that if we got divorced that he would do everything in his power to make sure that he got full custody of our son and that I would barely see him. I resent my husband for many things that he has said to tear me apart as a human being thoughtout our marriage like "you'll never be a good mother", "I don't even like you", or telling me that when we are on the escalator that I should go down in front of him holding my son because in case they fall, he would want it to be on top of me and he wouldn't care if I got hurt since our son is more important. I don't know what to do. I want out of this marriage, but I don't want to lose my son. 💔😭