My boyfriend is still friends with the girl he used to talk to before we got together

Maria
Okay so me and my boyfriend have been dating for a year and he still talks to the girl he used to talk too before we got together. He says they're just friends but are they really friends?? Last year he went to see her behind my back and I asked her who rose Mary was and he replied with he's just my coworker truth is It was actually her. He later told me that he had gone to see her that night and that she asked him if he was talking to me while he was talking to her. At this point we have been like 6 months together. Like why would she care. Later on his friends were together at a flag football and she had came. They asked us to go out to eat and he replied with a sure why not. Knowing that he have had a thing with her . He made me sit in a table with the girl he used to talk to not only that but when we were on our way to waffle house she stated that her feet were hurting cuz she was wearing high heels. What he did is that he took out a pair of extra shoes he had and gave them to her. I was so hurt that night and I dint know what to think. Last week I was going through his phone and I saw a conversation that they where having and she was talking to him about pussy juice and that she didn't wear no bras or underwear because she didn't like them. He would call himself big daddy to her and I was hurt once again. I asked him to block her off all he's social media and he replied to me with a "NOOO she's my friend" at this point I don't know what to think anymore . What do I do ???