The sense of being in love was something that neither Theo nor Draco were accustomed to. Theo had grown used to displays of emotion being decried for weakness and Draco had spent so many years perfecting his cold exterior that he had forgotten how to let his guard down.
Luna had love enough for both of them.
She was perpetually bubbling over with it, so much so that the boys felt guilty if they didn't reciprocate. Theo could smile or hug or kiss her without fear of reprimand, and Draco without fear of shame.
It was a wonderful, wonderful feeling.