My (28F) bf (27M) went to a strip club. How do I deal with this?

This is very embarrassing for me to post but it is something I need to do to move on. We have been together for almost two years so I am not gonna list the reasons why I was not expecting him to do it. He admitted to going to one for a bachelor party last weekend. I am so hurt and I havent been able to sleep or eat so much. I am definitely going to talk to him about it but for now I need advice. I just want some things to say to him. Is there anything I should not tell him? Some of you might think that I am being over sensitive but please help me.