The first U.S. soldier killed by enemy fire in Afghanistan was a quiet professional "who just wanted to change the world," his widow said.

Renae Chapman said she and Sgt. 1st Class Nathan Ross Chapman talked about his upcoming Special Forces duty before he left.

"I asked him, 'How important is it, do you want to go?' and he said, 'Yes, it is me, I have to go,"' his wife said Tuesday in a video interview set up by the Army.

She didn't know exactly what he would be doing and said to him, "That's OK, our guys aren't dying over there, we have 4,000 Marines over there ... you'll come home."

He told her, "Honey, there's a 50-50 chance I'm not coming home." He gave her a heart pendant, and they broke it so she could wear half — and then he left.

Chapman, a Green Beret communications specialist, died Friday when he was hit by small-arms fire in an ambush near the Afghan town of Khost. He and a CIA officer had been meeting with local tribal leaders.

Chapman was a graduate of Centerville High School near Dayton, Ohio.

Asked why her husband joined the Special Forces, she said, "That's so easy. He had seen so much of the world ... for instance he called me on satellite phone and he said he sees women and children being beaten with sticks just for walking down the street ... and he wanted to fight against that.

"He gave everything he had, everywhere he was, to everyone he knew," she said. "And he wanted to make everyone happy."

Renae Chapman also remembered his love for his children, Amanda, 2, and Brandon, 1.

"He never sat around. He was always, always doing something, taking them for a walk, giving them a bath, playing with them in the park," she said.

Chapman, 31, left her a videotape for their children, telling them of his love.

She thanked the Special Forces for all the support her children have received, saying, "Every day the guys in green come in and play and tickle and poke and giggle so they don't feel their daddy's so gone."

Asked about her husband's legacy, she said: "I want them to remember him as a quiet professional who just wanted to change the world."