Cheating on a spouse is more than just frowned upon in Colorado, it's illegal. Under a decades-old law, any married person who engages in sexual intercourse with someone other than their spouse can face up to $1,000 in fines, jail time, or both.

This week, state lawmakers will vote on House Bill 13-116 to repeal the adultery law.
The bill, back by Rep. Daniel Kagan (D- Cherry Hills Village) and Sen. Pat Steadman (D- Denver), would decriminalize adultery.

"[The law] injects the police and law enforcement into our private affairs in an unjustifiable and unwarranted way," Rep. Kagan said. "The deeper question is whether it should be an issue that involves the police, law enforcement and the courts, or whether it should be an issue that involves a person, their spouse, and their conscience."

The current law also prohibits hotels from renting rooms to unmarried couples who plan to engage in sexual activity. El Palomino Motel owner Iwona Kowalczuk said despite the law, she would never ask a guest such a personal question.

"This is privacy and we don't need to know if this is a married couple or single... it doesn't matter to me," Kowalczuk said.

Grand Junction mom Becky Dark said she wasn't aware the law existed, nor can she believe it exists.

"There's more important things to worry about than our personal relationships," Dark said. "You can't legislate morality."

Even though the law has existed for decades, prosecutions of it are rare. Over the last five years, just five people were accused of breaking the law and promoting sexual immorality.

In 2011, a similar bill to repeal the adultery law failed. Lawmakers then argued repealing the law would send the message that infidelity is acceptable.