
This list is on the yaoi side, but there is poly BL titles (with throuples) https://www.mangago.zone/home/mangalist/2345830/

I love that one. Please note this story is heavily psychological, it's R19+ and needs a trigger warning (ptsd with flashbacks from past trauma including SA... Not a lighthearted read. But very deep and realistic! The delivery is masterful. And i love how the three come together ! _ That story is trauma from the inside out. Don't read before sleep. (IF you choose to read it)
Bl with poly relationship