Iriel's partner doesn't harm him overtly. he wears him down.

He prepares "special" infusions and meals that supposedly regulate his scent and calm his anxiety, but leave him drowsy and mentally sluggish.

He adjusts his sleep routine so he sleeps too much... or poorly. Iriel never feels fully awake.

he reinforces the idea that his omega body is unstable, that going out or socializing could worsen his condition.

he interprets any sign of lucidity or energy as a "dangerous outbreak" that must be controlled.

Nothing seems violent. Everything seems carefully controlled.