He wasn't worried about getting attached. That ship had sailed. She couldn't spare him hurt by cutting things off now because it was already too late. He could be hurt now or hurt later and he'd choose later every time. Because you never knew what would happen in the future, and you should always seize something sweet even if it was fleeting.
"Well, I'm not worried." He met her eyes calmly. "I don't know what I could say to convince you of that. Either you trust me to deal with it or you don't. It's up to you."