am I overreacting?

Celiz

so my boyfriend has been hanging out with a new group of friends and a girl he use to be in love with hangs out with them and always offers to pick him up and hang with him. But he tells her "no". But now he asked me if it was fine with me if he could hang with her along with his other friends. And I really don't like that idea and when I told him he said "baby you're my number one. I'm not worried about any other girls" what should I do?