Xiu refers to Ahning as the woman he loves. Ahning just turned 18 in ep 20, however, she acts more like she's 15 or 16. I'm sure it's due to her sheltered upbringing but she's too childish for Xiu. He needs to find a strong woman that can stand at his side, not a girl that needs coddling.
Damn, it's too bad I can't watch this right now since I'm at my college and clearing out my digestive systems.