netorase
A fetish where the protagonist's love interest has sex with others, which the protagonist enjoys, actively encourages, or even causes and the love interest typically being unaware of the protagonist's intentions beforehand.
Not to be confused with the similarly worded netorare, which is the protagonist's partner being stolen against the protagonist's wishes.
If both parties consent to having the third party involved, use swinging instead. If the sexual relationship is without the protagonist's consent, uses cheating instead.
Examples
