Imo.. majority of women who like NTR are either into cheating (having sex with other man because they feel pleasure by doing something immoral) or sadism (cuckold - like torturing your BF, make him jealous and inferior to other man's dick or sex technique).
There is a different from how we as men view NTR as a fetish. Women don't really feel like excited from watching their BFs fucking other girls because they don't have this primal man's desire of owning/marking someone to be ours. Instead they have desire to be owned/marked. So you can guess where that will lead to. Women view cheating as pleasure for those who develop that fetish ofc.