In a poignantly personal interview with ABC News' Diane Sawyer, astronaut Capt. Mark Kelly opens up about his wife Gabrielle Giffords' recovery and the Tucson shooting that injured her and killed six people.
Kelly, who has been photographed by his wife's hospital bed holding her hand, said there is a habit of hers that has convinced him that she recognizes him.
"If I hold her hand, she'll play with my wedding ring," he said. "She'll move it up and down my finger. She'll take it off. ... She'll put it on her own finger. She'll move it to her thumb. And then she can put it back on my finger.
"The reason why I know that that means she recognizes me is because she's done that before. She'll do that if we're sitting in a restaurant. She'll do the same exact movements," he said.
Watch portions of Diane Sawyer's exclusive interview Tuesday on "Good Morning America," "World News with Diane Sawyer" and "Nightline." Watch the full interview on a special edition of "20/20," "The Congresswoman and the Astronaut: An American Story of Love and Strength," at 10 p.m. ET.
Kelly was struck by Giffords' progress again when "she stuck her hand up on the side of my face" and began giving him a neck massage.
"She spent 10 minutes rubbing my neck and I keep telling her, 'Gabby, you're in the ICU. You know, you don't need to be doing this," he said with a chuckle.
Kelly added, "I'm pretty sure she wouldn't do that to somebody else. And she's looking me in the eye."
Today's hopeful emotions are a world away from what was going through his mind a little more than a week ago when Kelly was in Houston and got a phone call from one of his wife's staffers, telling him his "Gabby" had been shot. He had spoken to his wife 30 minutes before.
"I picked up the phone and she says, 'I don't know how to tell you about this, but I just received a call ... and Gabby's been shot,'" Kelly told Sawyer. "I said, 'Well, that's, you know, that's not possible. Are you sure?'"
With no other information, Kelly ended the conversation and hung up his cell phone. He had to look at the phone's call history to make sure he hadn't imagined the news. He told his children -- Giffords' stepdaughters -- and then called Giffords' parents and his own. Then, there was one thought in his head.
"[I] quickly had to figure out how I'm going to get there very, you know, very fast," Kelly said.
Capt. Kelly admitted to Sawyer that he had been worried about his wife's safety in the past and that the two of them had discussed the death threats Giffords had received. "She's had death threats," he said. "As a lot of members of Congress have death threats. She's had them before."
Giffords has shared her own fears with her husband, telling him, "Someday, I'm really worried that somebody's going to come up to me at one of these events with a gun."
It was not an everyday fear but it was something that Giffords and Kelly took seriously enough to discuss a handful of times, he said.
When asked if he would ever be willing to meet with Loughner's parents, Kelly told Sawyer that he was open to the idea.
"I'd probably see them," he said. "I don't think it's their fault. It's not the parents' fault. I'd like to think I'm a person that's somewhat forgiving. And, I mean, they've got to be hurting in this situation as much as anybody.
Now in Tucson's University Hospital, Kelly is closely monitoring his wife's recovery, tackling every detail with the same focus he brings to his job as a space shuttle commander. In the first days after the attack, he slept in the hospital and only recently has begun to stay in a hotel across the street.
Although the couple owns a condo two miles away from the hospital, Kelly prefers to be as close as possible to his wife's bedside, where he tells her he loves her and reads out loud some of the thousands of supportive letters and e-mails that have flooded in since the attack.
So far, doctors say, Giffords' recovery has been nothing short of miraculous. She was removed from a ventilator Saturday and her condition was upgraded Monday to serious from critical.
Doctors have inserted a tracheotomy tube in her throat to help her breathe and put a feeding tube in her stomach.
While his wife has yet to speak or hint at how much she understands, Kelly has witnessed Giffords following instructions, like a command to hold up two fingers.
When Giffords does begin to speak, Kelly knows they have plenty to talk about. One of the "hardest things," he said, will be having to tell her about the six people who died in the attack, including one of her dedicated staffers, Gabe Zimmerman, and 9-year-old Christina-Taylor Green.
"I was at her funeral the other day," Kelly said. "For a 9-year-old girl to die, you know, just because she was interested in democracy? I mean, it's just not fair."
In the hospital's ICU, Kelly has also comforted Susan Heilman, the woman who brought Green to the supermarket and was also injured in the attack. He said Heilman spoke to Green seconds before the shoo0ting began.
"She leaned down next to her and said, 'You know, someday, you know, you could grow up and be like Gabrielle Giffords.' And those were the last words she heard," Kelly said. "I mean, you just can't explain it."
Capt. Kelly is also facing the question of his own future; whether he will be the commander of the final space shuttle mission April 19, known as STS-134.
His crew sent a supportive tweet this weekend, saying, "Gabby is improving. Mark is strong ... STS134 will succeed."
Whatever the final decision, Kelly's heart will be right there with his wife.
Inside his wife's wedding ring, he had a message inscribed -- "You're the closest to heaven that I've ever been."
Hear Sawyer's exclusive conversation with Kelly tonight on a special edition of "20/20," "The Congresswoman and the Astronaut: An American Story of Love and Strength," at 10 p.m. ET.