Colorado father Barry Morphew was arrested on murder charges earlier this week in connection with the Mother’s Day disappearance of his wife and the mother of their two daughters, Suzanne Morphew, roughly a year ago.

Investigators have not yet released a motive, and a trial date has not yet been set, but what would motivate a married person to kill their spouse?

Barry Morphew was arrested on Wednesday, May 5, in connection with the disappearance of his wife, Suzanne Morphew, who was last seen a year ago on Mother's Day, May 10, 2020.

Barry Morphew was arrested on Wednesday, May 5, in connection with the disappearance of his wife, Suzanne Morphew, who was last seen a year ago on Mother's Day, May 10, 2020. (KUSA via AP, Pool)

In some cases – killer husbands were dating other women, who eventually helped investigators solve the cases.

BARRY MORPHEW CHARGED WITH MURDER NEARLY ONE YEAR AFTER WIFE'S DISAPPEARANCE

California man Scott Peterson was convicted of murder in 2004 for killing his pregnant wife, Laci, and their unborn son. Police quickly closed in on him as a suspect after his girlfriend, Amber Frey, told them that she began dating him a month before the murders. She said he claimed when they met that his wife was already dead.

This May 11, 2018 photo from the California Department of Corrections and Rehabilitation shows Scott Peterson. (California Department of Corrections and Rehabilitation via AP, File)

This May 11, 2018 photo from the California Department of Corrections and Rehabilitation shows Scott Peterson. (California Department of Corrections and Rehabilitation via AP, File)

He has maintained his innocence and is appealing his conviction, and a judge overturned his death sentence last year.

Christopher Watts, of Colorado, killed his wife and their 3- and 4-year-old daughters while dating a woman named Nichol Kessinger, who told investigators that when she met him he’d told her he was already separated from Shanann Watts.

Christopher Watts was sentenced to life in prison for murdering his pregnant wife, and daughters. (RJ Sangosti/The Denver Post via Getty Images)

Christopher Watts was sentenced to life in prison for murdering his pregnant wife, and daughters. (RJ Sangosti/The Denver Post via Getty Images)

She was also pregnant at the time, according to the Denver Post. Kessinger wound up going to police and telling them Watts had lied to her about his marital status and could likely have been lying to police about his family’s whereabouts. When investigators examined her devices, they found she’d Googled, "Did people hate Amber Frey?"

Then there was Drew Peterson – a former Illinois police officer who was convicted in 2012 of the 2003 murder of his third wife, Kathleen Savio, in the months before their divorce.

FILE - In this May 8, 2009 file photo, former Bolingbrook, Ill., police officer Drew Peterson arrives for court in Joliet, Ill. Jury selection is set to begin Friday, May 20, 2016, in Chester, Ill., in the murder-for-hire trial of Peterson, who is accused of plotting to kill the prosecutor who put him behind bars in his third wife's death. (AP Photo/M. Spencer Green, File)

In this May 8, 2009 file photo, former Bolingbrook, Ill., police officer Drew Peterson arrives for court in Joliet, Ill. (AP)

Between her slaying and his conviction, his fourth wife, Stacy Ann Cales Peterson, vanished in 2007 and has never been found. They had married just eight days after Peterson and Savio’s divorce was finalized. A year and two months after his fourth wife’s disappearance, he was engaged to Christina Raines, according to ABC News, and she reportedly left him after seeing an interview with him on "Nightline."

And Gabriel Ferris, of Saginaw, Mich., strangled his ex-girlfriend Cheryl Miller shortly before taking off for a honeymoon with his new wife, who told detectives 20 years later she’d seen him suspiciously re-entering their lodging the morning the victim’s body had been discovered.

CLICK HERE FOR THE FOX NEWS APP

It’s unclear what led prosecutors to charge Barry Morphew this week in his wife’s disappearance, and 11th Judicial District Attorney Linda Stanley said court documents and sworn affidavits would remain sealed.

Barry Morphew previously said investigators were trying to blame him for the May 10 disappearance of his wife, Suzanne. He was arrested Wednesday and is charged with first-degree murder. (Courtesy of Suzanne Morphew's Family)

Barry Morphew previously said investigators were trying to blame him for the May 10 disappearance of his wife, Suzanne. He was arrested Wednesday and is charged with first-degree murder. (Courtesy of Suzanne Morphew's Family) (Courtesy of Suzanne Morphew's Family)

He was charged with first-degree murder after deliberation, tampering with physical evidence and attempt to influence a public servant, according to authorities.

Suzanne Morphew went missing on May 10, 2020 – Mother’s Day – after leaving her home for a bike ride. Her remains have still not been recovered.

The Associated Press contributed to this report.