Quote Quoting ConfusedDepressed
Is it considered adultry for a spouse to whisper about sex with someone other than their spouse and that person is of the opposite gender.
No.

Quote Quoting ConfusedDepressed
Is it acceptable, Especially when their spouse is within hearing proximity of the conversation?
It will depend upon the relationship. Absent consent from the partner, it seems quite rude. In some cases, it would arguably be mentally abusive.