From the perspective of the partner of a hot wife, as a “bull,” and cheater, for me the experience is a blend of psychological and sexual, probably biased toward the psychological aspects.
My obsession with cuckolding started relatively early, in my college years. It stems from the traumatic events associated with the dissolution of my engagement (although we reconciled, and have been married 40+ years). My then fiancé, now wife KK cheated on me. That triggered my fascination with this lifestyle.
A big part of this is related to seduction, to giving in to one’s lust, being driven by desire. There are aspects that range from the anticipation, and anxiety associated with planning an encounter. Finding a suitable partner, or partners, role-playing to heighten the build-up, and so on all are powerful psychological stimulants.
Through the lens of a cuckolded husband, the knowledge that your wife is fucking other men, and there’s little you can do about it, let alone voice objection is an interesting dynamic. Even more powerful is being present, or perhaps participating as she’s engaged in sex with another man, or men is beyond amazing, a multi-dimensional psychological thrill - the breaking of societal taboos, crossing boundaries, pushing limits is part of the experience.
There’s few comparable experiences like watching your wife in the throes of orgasm, while she’s riding another man’s hard cock. The sight of one’s wife, the center of attention for multiple men, giving herself to the extremes of pleasure in a gang bang is beyond description.
Through the lens of “bull” (I hate that term, but it simplifies conversation), or a man seducing another man’s wife there is an overwhelming sensation, a blended emotion associated with “taking” another man’s wife. The sensation is enhanced when the wife loses control, becoming “my slut."