Jack was supposed to be happy. He finally had everything that he ever wanted. Torchwood was back up and running after being rebuilt from the explosion that destroyed it. He was once again in charge with Gwen as his second in command. This time they had more employees though and he was able to leave each night without having to worry that the rift would be unattended while he was gone. Paperwork was finished by his secretary and thing were running smoother than ever. So why did he feel like something was missing? He missed the days of the cramped sewers and sleeping in the little room below his office. He longed to hear Myfanwy calling out as she circled the ceiling high above. Those days were over though and now each night he returned home to his family.
His two beautiful children adored him. It always cheered him up after a long day to walk in the house and see them running towards him. Bending down he would scoop his son and daughter into his arms kissing them on the heads as they jabbered on about their day. Being three their day didn't consist of much besides playing in the park or going shopping with their father. They were happy to tell him all about it though and he was just as happy to listen. His children were his universe now and he would have been lost without them. Maybe that is part of the reason he stayed.
Or it could have been that after thousands of years of waiting he finally got the man that he waited for. The Time Lord who had once run from him thinking he was wrong now shared his bed at night. He had taken Jack's hand in marriage willingly settling down to raise their twins. Though this Doctor wasn't the one with the northern accent Jack had first fallen in love with, nor was he the skinny man in the pin striped suit, he still held Jack's heart in his hands. Jack hadn't believed the man in the bowtie was really the Doctor at first, but his eyes told a different story. His eyes held the same haunted look as before only this time he didn't want to be alone. He had welcomed Jack into his hearts and his bed with very little convincing. The kisses came freely and he wanted Jack just as much as Jack had always wanted him. Only this time he didn't.
It was about a year after the twins were born that Jack realized he wasn't as happy as he thought. Though he loved his family his love for the Time Lord had faded. He fought himself to figure out why then late one night he did. Part of his love for the Doctor was the fact that the Time Lord would never be his. He was the one who was always just one step out of reach. The one he flirted and teased, never expecting him to actually love him back, no matter how hard he hoped he would. Now the Doctor had given him both hearts and part of that mystery about him was gone. He would walk with the Doctor, hand in hand, missing the chase. He thought of leaving for awhile. He couldn't do it, though.
The Doctor had finally opened up his hearts to love again and Jack wasn't going to be the one to destroy him. The Time Lord didn't deserve all of the pain that he had experienced in his life. He had lost his family, his planet and had to constantly travel on alone. If anyone in the universe deserved to feel love and be happy it was the Doctor. So despite his own love fading, Jack stayed with him. He kissed him good morning and held him at night as their bodies moved as one, anything to make the Time Lord believe he was truly happy. And sometimes just for a moment, he was.