After weighing the options, King Killian decided that it would be best not to fight what was happening to him. His body and mind, maybe even his soul, wanted totally different things and he had been pushing away what his mind and body wanted, trying to follow his soul…the part of him that wanted his curse broken more than anything.
So, after much deliberation, King Killian agreed not to fight with his mind and body no more. Instead of running away from Elena or avoiding her, hoping that he would get well soon, he would try to get used to her presence and fight the affection, instead.
With this plan, King Killian believed that he would gain control again once he got used to Elena's presence. The sooner his affection or whatever it was that was happening to him fades, the better for him.