While Viall might be convinced he found lasting love on Season 21 of The Bachelor, which wrapped late last year, the woman who received his final rose is appalled watching his promiscuous behavior on television -- and so is her family, In Touch Weeklyreported.
"Their opinions are important to her," a source close to the show told In Touch, adding that the winning bachelorette's family isn't too fond of Viall.
"Hearing their negative feedback has been really hard. At this point, she isn't sure she can move forward with marrying someone like Nick."
An insider previously told the magazine that Viall's last woman standing is wondering whether "maybe she made a huge mistake" in choosing to continue dating the Bachelor after the show.
"She's having second thoughts about spending the rest of her life with him," the insider had said. "[She is] so embarrassed by his behavior."
The bachelorette is reportedly having regrets because she's trying to stomach the fact Viall, 36, gets "a little too intimate" with multiple girls on the show. The winner reportedly ignored warnings from other girls during filming that Viall had tried to sleep with them.
"Nick is already very sweet and loving toward the winner in private, but she's starting to see how much of a playboy he is, thanks to the show," the insider told In Touch.
"Watching the show each week gets harder and harder for the winner because his behavior gets shadier and shadier."
So far this season, Viall licked whipped cream off villain Corinne Olympios' chest and also held her naked breasts during a group-date photo shoot.
Because of his apparent romantic interest in a woman leading with her sexuality, bachelorettes -- including frontrunners Raven Gates and Vanessa Grimaldi -- have questioned the Bachelor's intentions and whether he's truly looking for a future wife or just someone to mess around with.
SPOILERS: Click here to learn which bachelorette allegedly received Nick's final rose!