Should I be worried?

My boyfriend was talking to this girl when we had broke up and when we finally decided to talk things out and get back together he decided to tell the girl he was just rushing into things and blah blah blah. When we got back I told him to cut all conversations with this girl off firstly because she was talking to him while he was in a relationship with me and on top of that she told him she could make him cheat on me which he did not do! But what the problem is--is that I don’t want him associating with this girl anymore. He said he only talked to her because she had family issues and he’s always there to help and that doesn’t only go for her it goes for everyone, you see he likes to try and help out people with their situations and I don’t understand why. He gives advice but people don’t even take it and I feel as if he waste his time even talking to them.

I want our relationship to go through smoothly with no problems...but me knowing that he’s communicating with this girl that knows she’s in the wrong and he even mentions to me that those are red flags but then again I don’t understand why won’t he listen to me when I tell him to stop talking to her.