I'll preface this by saying that I'm not into the cuckolding thing so that's not what this is about.

My wife and I have been in the lifestyle a few years now. Mostly group stuff but some occasional solo fun as well. Something we've both discovered recently is that we enjoy the cheating fantasy where she has sex with someone else without my knowledge (I would then find out after).

She enjoys the idea because it's taboo and not something she ever did before and I enjoy the idea of her being insatiably aroused that she doesn't think straight.

We've talked about the fantasy before but unsure how we can act on it. The problem we have is that we're not in a non-monogamy headspace 24/7 and we're both a little paranoid that, if we did act on it, then it might fall on a day when I can't handle it. (I honestly think there's a higher likelihood I'd enjoy it but I'm the paranoid type.)

Is this a fantasy that anyone has indulged in and has any advice on how to approach, and act on, a cheating fantasy ethically? (An oxymoron if ever there was one!)