Can I get custody of my child if I am on SSI and can't work and I am the one who takes care of our child all the time?

I found out that my husband is planning to file for divorce and is also planning to try to take custody of our youngest child. He is the representative payee on my SSI. He has a very short temper and a shorter fuse and he very controlling and abusive to me not our child but has yelled at her before. I am a stay at home mom and the primary care giver and everything is in my name except the internet. Our child is a student at sc connections academy an online public charter school and he plans to try to use the fact it is not a brick and mortar school. The school is real and she has legitimate teachers. He is barely involved with her and when I ask him to attend appointments or activities with us, he usably declines even if he doesn't have to work. I have several people who know I am normally the one who is taking care of our child she is always with me. She also has a fear of sleeping in her room and he has tried to force her to and I am working on it. I have been sleeping on our couch for two years now because of him.