So sleeping with her can heal you

I don't think that's it. She only healed him midway. He was still quite injured when they banged, just not bleeding anymore.

That IS a manga, just not THIS manga. XD

Try this if you actually want that setup:
https://www.mangago.me/read-manga/healer_for_the_shadow_hero/

⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄ thanks