How do I get rid of the other woman?

About a month ago my boyfriend cheated on me with a neighbor. I found out about it, confronted him and now we are trying to work things out. He told me he wouldn't talk to her or her friend anymore but I know, for a fact, that he still talks to bother of them. There is no flirting or talk about sex...should I be concerned? Should I not wait around to find out what's going on? What should I do?