Is it sexual abuse that my mom shared way too much about her sex life?

My mom is... Fucking weird, to say the least. She has borderline personality disorder, PTSD, OCD, I mean these things per say don't make her weird. It's the fact that she refuses any help. I'm a young adult, I've just moved out, and I've started therapy for about the third time in my life. I grew up with my mother halftime, my parents are divorced, and my mom abused me for most of my childhood. Physically, mentally, emotionally. She would lock me in the basement when I was bad, give me bruises, the lot. She's a very... Open woman. She has been for most of my life. At the age of 4, I learned about sex. She drew an egg and a sperm, the sperm entering the egg, with little smily faces and everything. I didn't learn about the penis in vagina thing until I was about 7. When I was 12, it was like a floodgate opened. She started telling me everything about her sex life, from her and my dad having threesomes to her last boyfriend being uptight and not having sex with her when I was in the house. She bought a bunch of condoms, put them in a jar in the cupboard, and told me they were there when I needed them, because I shouldn't be getting pregnant. Again, I was 12. Condom wrappers were often left around her room and as I was older I started to realize that I was hearing her frequently and loudly having sex in the next room over. Thinking back, I started to realize that my mom often brought me along on her sexual encounters. At the age of 4, I remember being placed alone in a room as she went off with her "friend". That sort of thing only became more frequent as time went on.
So, I mentioned that I started therapy again recently. I needed therapy at a young age to help me cope with the physical trauma my mom inflicted upon me. I told my therapist about all of this, and she told me that this was considered sexual abuse. I guess I never really thought about it that way, but just add it on to the other abuse my mom gave me. What do you think? Does this count as sexual abuse?