What showed on Louis' face first must have been disappointment. Though he had been trying not to think too far ahead, part of his mind might have wandered forward a bit to the part where he might have a boyfriend he could take home to his family.
But Julius seemed so sincerely concerned, and after what Louis had gone through recently in being clumsily thrust out of the closet, he could not begrudge Julius his desire for privacy, especially if he was not fortunate enough to have a family so understanding as the Weasleys.
And so he nodded and said, "You can trust me. I understand. But it's... unfortunate, for you. I'm sorry." He brought a hand up to gently brush Julius' cheek with his fingers. He was such a terrible liar that his sincerity showed just as easily on his face.