ENM Cuckold relationships

Fmgf91

Couple
I know this may sound different but does anyone have a cuckold/vixen relationship with someone outside of the primary partner in an ENM relationship?

I am very turned on by the idea of a stag/vixen or even cuckold relationship but my girlfriend isn’t into it. She is open to me experiencing it with others but not herself.

Does anyone have an arrangement like this?