Pretty solid consensus, which I hope you take seriously. Emotions are, by definition, not rational, so no need to attempt to defend
them rationally. If yr not interested, yr not interested. Period.
Interesting that you are not, by yourself, sufficient for his erotic satisfaction. Is he playing the field and wants you to join in? Wants
your permission/approval? If playing without yr permission/approval, is he putting your health/life at risk from dishonesty?
Does he have any particular third person in mind? Who would get to choose?