The husband of a 21-year-old Serbian reality star has threatened to leave her after she was caught in bed with another man.

Milijana Bozic married Milojko Bozic, 74, in September this year and decided to appear in a reality TV show about couples.

However, during filming Milijana was caught sitting cross-legged on the lap of a 60-year-old fellow cast member and giving him a passionate kiss.

It was not the first time Milijana has been questioned on her infidelity so her made it clear he wasn't able to forgive his wife this time around.

Milijana and Milojko married in September this year. (Instagram)

"If you set it like this, our conflict will continue after the reality show," Bozic told the show.

"She's playing me and is making a fool out of me."

"This is not a game this is real! Milijana is playing both of us."

Prior to going on the show, Milijana was caught naked in bed with another man after somebody leaked selfies which she had taken in bed. It was reported by a local news outlet that she slept with the man while her husband lay in the bed next to them.

The unnamed man is said to be married with children and, in an extra sting, even attended the highly publicised wedding between Milijana and Bozic.

However, Milijana heavily disputes the claims saying the "person who posted those photos will be sued".

"They are selfies I took and I know who I sent the pictures to, and I know who posted them.

(Instagram)

"I have seen this man a couple of times, but I have not been in a relationship with him."

Milijana was also embroiled in rumours with another man last season on the show, who was 35-year-old, despite her publicly admitting that young men don't have a chance with her.

"The men on 'Couple's are mostly young," Milijana said.

"They don't have grey hair or wear glasses. So, they don't have a chance with me."