Ki-jun is thrice divorced.

He cannot have one-night stands.

Ki-jun got divorced because all his wives were different from him.

1. Na-rae was Ki-jun’s first wife aka his "ex-ex-ex wife."
      - According to Ki-jun, she had wanted an open marriage. ("We had different views on marriage.")
      - According to Na-rae, they split due to the power of words. It is implied that the poem (about insurance), ‘The Funeral of Words’ had something to do with this.

2. Ki-jun’s second aka his "ex-ex wife" followed her purpose to became a female monk after an amicable split. ( "We had different worldviews.")

3. Ki-jun’s third aka his "ex-wife" and the circumstances surrounding their separation is yet to be revealed. ("We had different views on life.")

(NOTE: This discussion has been altered from its original topic, tag recommendations—I had suggested Romance which has been added.)

And "Business" as genre