+ your character ends up having to stay at her workmate/employee/boss's house for the weekend, perhaps her apartment complex is being fumigated, or some other reason. they've always been a flirty work couple (perhaps despite an age difference either way) but there's always been a palpable tension. now she's sleeping in his bed while he takes the couch, wearing one of his old shirts and rooting around his toy chest and bedside table to see what her work husband is into.
+ she helps her horny friends out by whoring her husband out to them. maybe this is an already established business for impregnating single women that's just keeping on schedule. if he can't make a home delivery she'll milk him and sell the filled condoms. maybe he's hired out as a stripper with lax rules on groping. he knows his place as a cum factory. you'd play the female characters.
+ a dominant woman is quarantined away from her two male subs. they're straight, but eager to take orders and show off over cam for her pleasure. she's in the mood for some awkward, hesitant, hot homemade gay porn. i'd play both subs.
+ they've always been obsessed with dares. it started simple enough, a naughty act or a sexy outfit in the privacy of their own home, but lately it's been spilling into public settings for the ultimate thrill. maybe two bored desk workers (business/finance/computers/telemarketer s/librarians/teachers) who play sexual dare games during office hours?
+ a straight guy and his wife/girlfriend/occasional hatefuck hookup start exploring pegging/anal play. she blindfolds him and gets one of her male friends to fuck him. maybe she wants to see him with another man, maybe she's getting revenge. seeking either the third party or the woman with npcs as necessary.
+ she's a camgirl, he's her favorite vintage pornstar looking to get with the times. alternatively, maybe he's her teacher, boss, roommate, stepfather, etc and uses her laptop to look at porn and jerk off while shes still broadcasting.
+ she and her husband have an understanding: she goes out and fucks whoever she wants, he waits patiently to see if he's allowed to clean her off afterwards.
+ he cheats on her for the second time - in order to win her back, he agrees to wear a chastity cage until she says he can stop. perhaps she's already tossed the key into the ocean before even realizing she might want to stick around and have a little fun.
+ they have an option relationship so she can explore sex with women, and occasionally she brings home her fuck buddies so they can experience her husband's girthy cock and eager tongue.
+ she meets someone she knows (boss, teacher, coach, friend's father, stepdad, ex, etc.) at a sex party all plugged up, gagged and blindfolded, and can't help but have a little fun.
+ her husband isn't conventionally attractive, but she wants to take him to a local sex party to show him how popular his sinfully submissive behavior makes him.
+ the king and queen of neighboring kingdoms are fierce rivals and even fiercer lovers. when she conquers his kingdom, she decides public humiliation is more fitting than public execution - and perhaps a cozy life of sexual servitude to her.
+ he's humiliated when his wife signs him up for classes to improve his lovemaking, but starts to reconsider when he realizes how hands on the new teacher is.
// open to suggestions for lines if you've been searching for anything in particular!