Former Secret Service Officer Gary Byrne’s exposé of the Clintons is already #1 on Amazon — and he’s just now starting to talk.

Byrne appeared on Fox News last night and revealed there was concern about what do to when there was an apparent “domestic dispute” between Bill and Hillary Clinton in the White House.

Byrne’s book, “Crisis of Character: A White House Secret Service Officer Discloses His Firsthand Experience with Hillary, Bill, and How They Operate,” describes an incident during the night in which a vase was broken and the next morning, the president attempted to hide a black eye with makeup.

According to the former officer, a White House staffer claimed the president’s injury was the result of an allergic reaction to coffee.

But the incident presented a conundrum: when Clinton’s spouse — who is also under Secret Service protection — poses a threat to the president, who gets protected?

Byrne agreed with Hannity’s assessment that is was a “crisis” for the agency and the host’s description that the president’s own wife “was a physical threat.”

“It was a concern. I’ve discussed it with other officers at the time, and agents: What do you do about a domestic dispute?

“Each situation is different,” Byrne responded when host Sean Hannity asked him for the answer.

“You know you have to protect the president — the protectee — and you have to protect the First Lady, but if he gets caught with some woman and she goes ballistic, then what happens, happens,” Byrne said.

He agreed with Hannity’s assessment that Hillary is “often angry.”

“I feel so strongly that people need to know the real Hillary Clinton and how dangerous she is in her behavior,” Byrne said.

“She is not a leader. She doesn’t have the temperament. She didn’t have the temperament to handle the social office when she was First Lady,” he said.