Boyfriend has gotten kinky with girls before me

So me and my bf are quite kinky in bed and earlier he was telling me about a fantasy he had about me and he said something that made me want to ask if he had done it with someone before and he said yes which really got to me because All this time I thought he never got this intimate with someone before and I told him that this upsets me. He reassured me and said he just had a hazy month where he tried some stuff like this which made me feel objectified and like I don’t want to be treated the same way he treated some girl he hooked up with like this, I told him that and of course he said that it’s different with me and I’m special and he loves me. But I can’t help but feel not too excited to do any kinky stuff anymore. Idk what to do or if I’m even allowed to be mad at this. I feel like I need some sense knocked into me. any advice?