Would you tell her?

I’m friends with my man’s best friends woman. We’re pretty much family at this point.

The man has been texting and trying to sleep with his woman’s best friend. He says his woman knows and gave him permission but I don’t think I believe that.

My man doesn’t want me to get in the middle becuz it’s not my business but I feel she deserves to know what her man is doing.. unless she really does know but what woman is going to be ok with their man messing around with their best friend?

I don’t know what to do. I hate drama and don’t want in the middle but I just feel like she should know.. any advice?