Not many manga suggestions but…here you go (also warning, most of these traumas are SA related to if you don’t want to read that, then skip).
Manga:
https://www.mangago.zone/read-manga/hakidame_to_tsuru/
https://www.mangago.zone/read-manga/hitori_to_hitori_no_3650nichi/ (idk if it’s trauma, or simply regret from the past that causes him to engage in/accept the behavior he encounters now)
Manhwa:
https://www.mangago.zone/read-manga/palace_of_bardo/
https://www.mangago.zone/read-manga/ouroboros_1/ (imo, one of the best ones that show how trauma can impact them. Shows how he copes with his trauma, even if it’s not in a healthy way)
https://www.mangago.zone/read-manga/incidentally_living_together/ (Not SA related)
https://www.mangago.zone/read-manga/my_hyung_s_lover/ (definitely trauma there even if they don’t explicitly say it. Continuing abuse. Everyone in this story is a red flag, including the uke tbh)
Hadakeru Kaibutsu (Yaoi)
Uke with trauma reccs please
(Would love if it was a manga)