Boyfriends family bad influence HELP ASAP

Me and my boyfriend have been together for 2 1/2 years. In the beginning of our relationship his cousins were bad influencers. I’m not saying he’s not at fault for the hurt he caused me I’m saying that him and his cousins were always jerks. All they talked about was women. The cousin had a girlfriend for 5 years and was always cheating and they all thought it was funny. They all talked about girls everyday. Sent pictures of other girls and all this other stuff. Over time he’s changed he grew up. He’s a very good guy. He is hard working, he is romantic, he treats me right. He is always fighting for our relationship. I’ve tried to walk away when things have gotten hard and he’s our rock. I think in some ways he wants to prove his commitment and loyalty to me now because I stayed through his mistakes. But I feel a stomach pain every time his cousins come up. I don’t want him to hang out with them or even talk to them. He doesn’t bring them up anymore, after I expressed my concerns of not being a big fan of them. He says he won’t do anything to hurt me. For over a year we’ve been working on the trust in our relationship. I’ve been trying really hard. But I’m scared. I need advice