The Doctor was pleased when he saw Jack smiling, he knew that Jack was happy from what he said, He blushed when Jack took his hand and he walked up to the front door with him.
He though smiled too and he looked at the girl in front of him as she opened the door. "Ah Happy Birthday." he was smiling happily. He looked at Jack and then at Arwen "I'm The Doctor." he shook her hand, He blushed when Jack mentioned he was his boyfriend, he really couldn't help that, The Doctor just seemed to easily blush "Ah Yeah , I have known Jack for a long time now, But I had things to do for awhile and Jack had to stay with his team," He really had missed Jack.
He was looking at Arwen "So 18th birthday exciting," he was grinning. He then looked back at Jack "So how long have you known Arwen," he was interested as he was sure Jack hadn't known her when they last saw each other.