Cuckoldry is sexual infidelity committed by a female to her boyfriend or husband.
Some females get off by participating in quasi-cuckoldry. This involves having casual sex with a slayer, right before dating a beta provider or right before committing to a beta provider. This leaves the beta provider a risk of providing for the child that's not his own. Lying about her past experiences with other men is another form of quasi-cuckoldry. (See also Slutting it up with the slayers)
Slayers also get off by participating in quasi-cuckoldry. This involves hiding the identities of the females he has had sex with. Later when the females find their own boyfriends, they would be unaware of her past sexual experiences. The slayer will get off at the thought of their boyfriends providing for them (who used to gave him sex for free).