There are some spoilers in this, and the content tends towards being somewhat darker.

Khimi lost his virginity to Lumi. After he fled from his family, he spent years as a mercenary and had plenty of opportunities to have sex, but would often deny them. However, he would go to brothels sometimes and watch, or do other things to stimulate himself. Despite the fact that he was a virgin, Khimi would never allow that to show through his love-making. He tries to hold himself together and at least act experienced, despite his lack of experience himself.

One of Lumi’s last memories of his home was being beaten and taken advantage of by his brother. Ultimately, he is ashamed and feels that he disappointed in himself for not being stronger.

The first time Lumi and Khimi are together, Lumi lies about having never been with anyone, because he wants to avoid having to tell him. Eventually it does become something they address and work at together.

In a perfect world, they would have lost their virginity to one another, but it’s not a perfect work.