There are certain ways to know if your partner in a relationship is lying to you about Cheat!ng. These are some of those ways.

You’ve got a feeling your significant other is up to no good. But even if your intuition is right, changes are he’s not going to answer your prompts with, “Yes, dear, I am Cheat!ng on you.”

So short of hooking him up to a lie-detector test or sticking him with truth serum, how can you know if he’s lying to you? Polygraph examiner and former FBI agent Jack Trimarco and body-language pro Lillian Glass, Ph.D., author of The Body Language of Liars, share the six “tells” he’s lying through his teeth.

1. He Acts Differently

Lie-detector tests are all about measuring changes from the norm, be that in terms of heart rate, breathing, or blood pressure. Likewise, when you’re investigating your guy’s possible misdeeds, any changes from his normal behavior point to dishonesty, says Trimarco. For example, if you ask where he was Friday night and he suddenly starts scratching his nose, clearing his throat, and breathing heavily, something’s amiss, says Glass.

2. He Overcompensates

Guys know that looking down is a telltale sign of lying. So when they lie, they typically make a point to look you in the eye, says Trimarco. Problem/good thing is, they typically overcompensate and go too far the other way. If he creepily stares you down (no blinking!) when he tells you, “No, I haven’t slept with anyone else,” he might as well be staring at his shoes, says Glass.

3. He Answers Your Question With A Question

You: “Are you Cheat!ng on me?” Him: “Am I Cheat!ng on you?… of course not!” Answering your question with a question buys him time to think of something believable to respond with, says Trimarco. He might be doing it consciously or unconsciously, but either way, what he says next is probably going to be a lie.

4. He Turns The Tables On You

“When people are guilty, they tend to turn the accusations around to whoever made it,” says Trimarco. He might say you’re putting past relationship baggage on him, that you’re paranoid, or that you’re probably Cheat!ng on him. “When he feels caught, he will want to take the heat off of himself and put you on the defense,” says Glass

5. His Story Keeps Changing

“The truth is constant, clear, and easy to remember. Lies, however, tend to change,” says Trimarco. If you start to notice changes in his story, or if, when you ask him what he did at his friend’s bachelor party, his answer is different than it was before, something’s up.

6. He Swears On His Mother’S Grave

“Innocent people don’t swear on the grave of their mother,” says Trimarco. “If he does, that’s a huge red flag.”

The truth is strong enough to stand on its own, so if he’s trying to prove his case with things that have nothing to do with the subject at hand (momma’s grave, unborn children, and God), he likely knows his defense is paper-thin.