A Staten Island man has been charged with gunning down his wife inside the couple’s home as their two teenage sons slept in another room, cops said.

Kevin Smith, 40, was charged Saturday with murder and weapons possession for fatally shooting Nikia Webster, 38, in the head inside their South Ave. home near Arlington Place in Mariners Harbor about 11:30 p.m. Wednesday.

When police arrived at the scene, Smith was nowhere to be found. The couple’s two teens were home, but did not witness the shooting.

The husband from hell was arrested outside his lawyer’s Brooklyn office Thursday afternoon, Webster’s relatives said. His lawyer was in the process of brokering a surrender when Smith was taken into custody.

The murder weapon was still on him, along with another unregistered firearm, according to court documents.

A Staten Island Criminal Court judge ordered Smith held without bail at a brief arraignment Saturday.

The slain woman’s family told the Daily News on Thursday that they saw no signs of strife in Webster’s seven-year marriage to Smith.

“They were a happy couple. When I saw them on Sunday they were fine — they were happy, we were all happy,” Webster’s grandmother, Alice Webster, 84, said. “We went to her mother’s grave. We sang, we read the Bible, we came back and had dinner. Everything was fine.”

Smith had practiced using handguns and posted an Instagram photo of himself at a firing range on Oct. 7.