I take no real umbrage with multiple partners as it really depends on how it's handled. I'll use Rose as an example... the idea of her running a train holds no interest to me because I find it impossible to believe. It requires an impossible suspension of disbelief. It's predicated on the notion that Rose, who has up to this point been an entirely unwilling participant in sexual acts with the duke, will suddenly be okay with fucking around, and that absolutely no one will recognize the large breasted, pink haired woman in her early 20s as their literal uncrowned queen. Sex with someone other than the duke would require Rose's morals to have degraded significantly between 12 and 13 without some kind of major extenuating circumstance which, honestly, I would have a hard time believing would be anything short of her having extremely disappointing sex with Leto or being let down by him to such an extreme degree that it overrides her intellect.
I have a similar view with Haylen and Lily. Haylen is a nun and a fuck pile just does not fit with her personality, and Lily is using her sexuality to get ahead in life and taking a ride around the block would be a pretty severe jump for her currently. Cyanna, though, can sit and spin on as many dicks as she wants. Of all the characters, even secondary ones, Cyanna is in a position where whoring out makes sense. She's not in a positive relationship of any kind, her current sexual partner is a cruel, manipulative, manchild asshole who can't seem to have sex with her without being emotionally abusive, and she's constantly surrounded by people having sex when they shouldn't be. Cyanna cracking and winding up giving into her desire to feel better makes more sense for her than it does anyone else on the cast.
I have a similar view with Haylen and Lily. Haylen is a nun and a fuck pile just does not fit with her personality, and Lily is using her sexuality to get ahead in life and taking a ride around the block would be a pretty severe jump for her currently. Cyanna, though, can sit and spin on as many dicks as she wants. Of all the characters, even secondary ones, Cyanna is in a position where whoring out makes sense. She's not in a positive relationship of any kind, her current sexual partner is a cruel, manipulative, manchild asshole who can't seem to have sex with her without being emotionally abusive, and she's constantly surrounded by people having sex when they shouldn't be. Cyanna cracking and winding up giving into her desire to feel better makes more sense for her than it does anyone else on the cast.