He’s belittling me..

So my boyfriend of 4 years has started treating me like shit. Belittles me in front of his friends and family. Tried to give off the impression he’s the top shit but in all honesty, it’s like he’s trying to control me. He told me today I couldn’t go see my mum because I’m seeing her tomorrow. He’s moved his daughter back in with us, she doesn’t like me and it’s a horrible atmosphere when they are together. He takes the piss out of me more when she’s there so that he gets a reaction from her and makes me look like the bad guy all the time. I’m thoroughly sick of everything. I don’t know how much more my mental health can take, I’m on the verge of a breakdown and he just doesn’t get it. I just needed to vent to be honest 😢