Adult Fiction: Spy is gifted a concubine, due to explosion she becomes blind, they fall in love and disappear forever

I think it was a fluff piece, but I read it back in 2005 and I remember a lot of details, apart from the title and author. The title started with a 'T', as far as I remember.
Scenes I remember:
-Mixed race concubine is gifted to a spy/adventurer for 1 or 5 year(s).
-They have an active sex life, which includes a scene in which they are in a hot room and have tantric sex without touching each other.
-He goes to a cave at one point, where he brews really strong tea.
-He tells a story about a naked woman covered in golden hair all over, and she lies on her back in the forest seducing men to have sex with her till they die
-There is an explosion in their house which causes her to go blind.
-Despite her 'disfigurement' he still likes her.
-It ends with them pretending to be dead but in actuality are alive.

Possibly Shibumi by Trevanian?

That would be it!
I must say I had a very different image of it stored in my mind as compared to what it actually is about.
Thank you! I had been searching for this book for some time.