Serial killer's ex-wife slept beside murderer for 8 years, never suspected his deadly double life

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For years, Bonnie Lou Gower shared a bed with a man she thought she knew better than anyone. She had no idea the man sleeping beside her was capable of murder.

Her husband, Richard "Marc" Evonitz, was leading a double life, one that would ultimately expose him as a serial killer who preyed on young girls.

His victims included a 16-year-old who lost her life while Evonitz was still married to Gower.

Decades after Evonitzs crimes came to light, Gower is revisiting the warning signs she didn't recognize — alongside the young woman who survived him.

In Investigation Discoverys "The Serial Killer Connection," Gower meets with Kara Robinson Chamberlain, who endured 18 hours of captivity and torture before escaping Evonitz, as they investigate whether he may be linked to other unsolved cases.

For Gower, one question has followed her since learning the truth about the man she married.

"When I initially learned about [his crimes] and I told people, honestly their first response is, Well, obviously you knew. How could you not have known?" Gower told Fox News Digital.

"That was my very first question to the FBI. How could I not know this? How could I not know I was sleeping next to somebody for eight and a half years that was doing this? And of course, they assured me that theres no way I could have known."

Looking back, Gower admitted there were things she didnt question at the time.

Whenever she left town to visit family, Evonitz insisted on staying behind, claiming he had to work. Only later did Gower discover that he had actually taken time off while she was away.

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"One of the reasons he never came with me was because he said he was working," said Gower.

"And then, I come to find out, he had actually taken off work on the days that I was out of town. But at the time, I wasnt at all concerned about leaving him behind. I was just going and visiting my family. It definitely makes you look at everybody and everything now, whether you can trust someones words or actions."

Gower met Evonitz, who was eight years her senior, . He was the older brother of one of her friends and would come home whenever he was on leave from the U.S. Navy. She quickly developed a crush on him as she got to know him and, at age 16, Evonitz asked her out on a date.

They married in August 1988 when she was 17 and he was 25.

"You think you know who you are when youre 17, but I really dont think I did," said Gower. "I dont think I had a handle on that. And I was relatively sheltered. I was very naïve, very trusting, taking everything at face value. I think he knew that."

During the marriage, there were moments when Gower suspected Evonitz was being unfaithful. Whenever she questioned him, Evonitz told her it was all in her head. She believed him. But as the relationship progressed, Evonitz began isolating her from friends and family as they moved around the country, from Maine to San Diego to Virginia.

"No one ever thinks that their significant other is going to be a serial killer," Chamberlain told Fox News Digital. "I think worst case, and this is something that she expressed to me, he was having an affair. No one ever thinks your spouse is out murdering someone."

"He kept that part of himself very tightly controlled and didnt show it to the people he was closest to."

The marriage began to unravel after Evonitz left the Navy. Gower said financial pressures fueled growing tensions between the couple, while Evonitz became prone to mood swings and what she described as "rages." He also frequently criticized her weight. Behind closed doors, Gower was