Separation

I just text my Baby Dad out of the house. He was emotionally and physically abused towards me now he’s coming around saying that he wants to split custody 50-50 saying that he wants one week on one week off my son is only 16 months old. I think that’s way too young to be bouncing around from house to house as I am his primary caregiver And I take care of him 90% of the time I’ve contacted Lawyer and I’m going to be getting in touch with her tomorrow. I’m not sure if I’m allowed to keep my son until there is a custody order in place I really don’t want to give him to my Baby Dad for a week as I feel as if he cannot take care of him properly and his parents just wanted my son because they have a weird obsession with him. Please if anyone has been through this I need advice