Boyfriend sending friends my nudes

So I've sent my boyfriend some pictures here and there and the other day I was looking trough his Snapchat conversation with his friend. He's never talked about this friend before so I was curious who it was, only reason I clicked on it. I saw this. I don't know what to say to him. I was angry, I was hurt. I'm confused. I don't know how to react and I'm unsure how I go on with talking about this. Am I overreacting?? Just need another gal's input 😅 also side note: I saw another convo between him and this guy and it suggested that he had sent pictures of me to him and he said "it's just a joke I would never send your pictures" like!!!! What?? I'm very concerned that he lied about it thinking I wouldn't find out. I hope I worded this story right 😅