I wonder whether you may need to help me. Please accept my

Hi, i wonder whether you may need to help me. Please accept my apologies for the long message. My ex and I both have parental responsibility for my son, He has regular visits with my ex, visiting on a tuesday after school for a few hours, and then he stays with him overnight, usually on a friday.
JA: What steps have you taken? Have you filed any papers in the family court?
Customer: we have been working with the school and SAFE ealing due to constant belittling of my sons feelings by my ex, constant remakes abut how soft he is, how hes gay for wearing skinny jeans, previously how he's stupid, or stroppy ect. On his last overnight visit with his father, he came home with a large bruise. When i asked my Ex about it, he admitted that it was him, he hadnt meant to bruise him, but my child was being stroppy. I asked my child and he said that his dad ran up the stairs after him, Grabbed his arm, Threw him on the bed and whilst jabbing him in the shoulder, told him he had crossed the line. I've now discussed this with SAFE ealing and they've advised i take legal advice to stop access as not only has there now been a physical action, but continued contact is effecting my sons self esteem. I dont know what i am supposed to do, how i go about this, what my rights are ect. my son is 9
JA: Have you talked to a lawyer about this yet?
Customer: no yet, this is me reaching out.
JA: Is there anything else the Lawyer should know before I connect you? Rest assured that they'll be able to help you.
Customer: This has been an ongoing situation for the last 3-4 years, with no change in behavior and no willingness to fix himself from my sons father thank you