Damon knew that he had said those words to her before but somehow it felt so much better when he was saying them in return to her own declaration. And he felt a lot freer about telling her that he loved her, knowing that she felt the same way about him. That no sire bond existed between them and she was free to make her own choice and her choice was him, because she loved him.
Damon hadn't felt this way since the night they had shared together before he knew about the sire bond and he believed that what Elena felt for him was real, that she wanted him and not Stefan. And that had all been real too. The sire bond wouldn't have been able to fake her feelings that night if her feelings for him were real all along, and that brought him joy he never knew he'd feel.
Going from being the one that Elena decided to let go the night she died to the man she now counted and depended on and loved was a huge step and he wanted to make sure that he didn't do anything to screw this up. He knew that he inevitably sabotaged things but he didn't want to do that with Elena, he wanted to do the right thing for once and he only hoped that he could pull that off.
The feel of her lips pressed against his left him in doubt of the way she felt about him. How could he doubt it when she poured her heart and soul into that kiss. Stefan was the furthest thing from his mind right now, too wrapped up in the fact that he was kissing Elena. The woman that he loved, that loved him back.
He noticed the smile on her face and he returned it. She had such a gorgeous smile.
"Hmm, let me think about that," he said. He returned the kiss, sliding his arms around her and pulling her toward him to deepen the kiss. "Of course you can stay. You'll be lucky if I let you leave," he murmured against her lips.