"But yeah, obviously we weren't ready. Like I said in the beginning, I thought I was strong enough for this and I totally wasn't."
Be fair to yourself. You thought you were strong enough for poly and, who knows, maybe you would have been if you were treated to a healthy, respectful poly relationship that moved at the pace that had been agreed to! Not being strong enough to respond well in the face of cheating and deception is not the same thing as not being strong enough for poly.
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.