That's probably because he views love beyond the physical measures which is one of the core components evidently found in the book. That doesn't mean it's not important for him. It is. But to him it was probably to read books together while lying on each other's laps. To educate one another to be better versions of themselves. The love making comes later after enough spiritual awakening between the couple. A good example of that would be the incident on their wedding night as he wanted to make love to her as soon as he saw her but he controlled his urges. For his core belief is love begins with spiritual connectedness first. Then, it is possible that Kimya's impatience and strong urges of making love to him turned him off altogether, where he expected to educate her on the matter first in accordance with his character traits of an enlightener in the book.
Even though it can be counted as unfair or even a lapse of judgement from Shams' end for Kimya, it was refreshing how he's also shown as a round character possessing much unpredictability and complexity.