Cuckolding is a fetish practice that involves a married couple (the wife-queen, and husband-cuck) and one additional partner (the Bull). In a hetero relationship, the cuck watches the Queen in a sexual dynamic with the Bull. However, this is not a purely heterosexual practice, and the cuck or Bull may be female.
Cuckolding is not the same as polyamory, ethical non-monogamy, or swinging.
Polyamory involves the committed relationship between three or more partners. Ethical non-monogamy refers to the practice of open relations which do not always involve a relationship between the committed couple, but does require honesty and openness about the other involved parties. Swinging involves the sexual interaction between two (or more) committed couples, but the outside relationships are kept to the outer bounds of time spent with the other established couple.
Cuckolding involves partners in a committed relationship bringing in another participant to have sex with one of the committed partners as the other partner watches. One or both partners may participate in sexual activities with the Bull. Sometimes, the cuck requests to be humiliated, teased, or kept chaste during the interaction.
Hotwives are not the same as Queens (or Queens of Spades).
Hotwives are women who, with full consent of their husbands, sleep with other partners for the sexual pleasure aspect. It has very little to do with humiliation of the partner (normally male) and more of the pride of sharing a sexy wife with another man. Queens of Spades are non-black women who prefer black lovers (BBC).
Start slow...
If you or your partner are interested in cuckolding, it's best to start slowly unless you both have experience with threesomes together; you'll also want to ensure that you have a deep trust bond and honest channels of communication. If you're a newbie to the kink scene, try erotic activities alone where you discuss sex with a past partner in detail. If you can handle that, your next step would be to watch your partner flirt from across the room. You can try closing in the distance, if you feel comfortable. Finally, be sure to discuss emotional, physical, and sexual safety completely with your partner before inviting anyone else into the bedroom.
Cuckolding benefits for Queens:
Cuckolding can add a spicy dimension to your vanilla sex.
It can place a woman in the 'power seat' for the evening.
The act of sleeping with another person can teach her new tricks to use with her committed partner.
Jealousy can increase the sexual drive for the male partner, lending to more vigorous and longer sexual encounters.
Cuckolding benefits for cucks:
Cuckolding can add a spicy dimension to your vanilla sex.
Watching your partner experience pleasure increases compersion (the happiness you feel when your partner is happy).
Submission and humiliation can be included in this practice.
Cuckolding benefits for Bulls:
You get to have no-strings-attached sex with someone who is eager and willing.
If you're into it, voyeurism and domination aspects are a prevalent part of this play.