Yes, if someone ignores you, breaks the boundaries that you jointly set, and then spreads disrespectful lies about you, you shouldn't sleep with them. Or even be friends with them. How does this not go without saying?
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.