Simply put, it was an arranged marriage to solidify his position as emperor by marrying you and gaining the support of your powerful family. He was a wild and bright man who blatantly spend more of his time with his concubine only to elicit a reaction out of you. He wanted to test just how much you can endure his attitude. He sought to break through your icy exterior. He constantly fails, though, since you always choose to ignore him, unfazed by his attempts to get a reaction out of you.