I agree with the others! It does not sound like your wife is too enthusiastic about it, but she also doesn’t want to hold you back from experiences you really want. She doesn’t want to know about it because it would obviously bother her to know.

I know how you feel! I’ve had one sexual partner (My BF) and he’s had several others, and for a while I was tormented by the fantasy of exploring other men sexually. I value our relationship and I don’t want the possibility of my want to explore sexually get in the way of how things are.

You might not like it, she might start to see you differently, she might start feeling insecure about what she can provide sexually, she might worry you’ll want to keep exploring, you might want to explore it more than once, you might feel guilty about it, you might have a negative experience etc. Those are all possibilities and not worth potentially ruining something solid for a craving.