Forcing you to spend your nights in bed with someone who is kinda-sorta your ex (more like it didn't happen in the first place than that it ended, but still, it'd have to be a sore spot), and to spend your days with no escape from your partner's NRE sounds like a concerted plan of torture. Wtf? They both really need to be more considerate of you. NRE makes people dumb, but this can't keep going.
Why is their discomfort over judgy roommates more important than your discomfort over having lost your safe space at home? And it's a shame about K's heart condition, but are these attacks going to stop sometime soon? If not, is her and A sleeping together every night going to go on indefinitely? That's not fair to you. K managed before (I assume this isn't new?) and she can continue to manage. Separate space is not some selfish desire of yours, it's a mental and emotional need that they are depriving you of. Not, not cool.
RP's proposal is a very fair one.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.