IMHO, you don't necessarily have to tell him you called that female. But you do need to recognize that your issue is not with her, but with him. I think you know that, yourself.

Since this has happened before, you have to wonder about your man's commitment. Sounds like he wants to keep shopping around, while having the security of someone always available to him. You might want to tell him that he can't have his cake and eat it too.

If fidelity is hard for him this early in the relationship, it probably won't be easier for him in years to come. You might want to cut your losses and not invest more in this guy.

So he tells you that this young lady is "ugly?" But she has his number and the idea that she can call him. She got both those things from him, I'm thinking. Imagine if she wasn't ugly.

If you two are living together, then you might want to rethink that arrangement.