8 signs your partner is lying to you

• If your partner accuses you of lying or says that they never lie, they might not be telling the truth.
• Avoiding eye contact if they usually make it could mean they're hiding something.
• If people tell you that your partner is lying to you, it's worth talking to them about it.

While everybody tells little white lies from time to time, some forms of deception are more serious than others in romantic relationships. 

INSIDER asked both relationship experts and a behavioral analysis interrogator about how to tell when your partner isn't being honest with you.

Here are eight signs that your partner might not be telling the truth.

They're acting differently

Lie detection is predicated on a baseline — the way someone normally behaves. Deviations from that baseline indicate that a person is under stress, possibly because they're being deceptive. 

Maybe they're bowing out of plans more often, or acting more distant lately. Maybe they're overloading you with affection in a way that seems odd. Whatever it is, if you notice that your partner is acting different, that can be a sign that something is up. 

"Look for changes in behavior," said Rachel Sussman, a relationship expert and marriage counselor in New York City. "That always means something."

Their social media posts contradict what they're telling you

If your partner told you that they were going to be one place, but show up on Instagram somewhere else, their plans could have changed — or they weren't honest about their plans in the first place.

"I've definitely heard those stories," said Sussman. "I've heard that one person says they're somewhere and then one of their friends that they're supposed to be with posts that they're not there."

Sussman also recommends that couples establish social media rules to avoid hurt feelings.

They say they never lie

"If somebody says they don't lie, they're lying," Roger Strecker, a behavioral analysis interrogator with 32 years of experience in law enforcement, previously told INSIDER. 

Everyone tells little white lies from time to time, and sometimes these little lies are ok, but Sussman distinguishes between small fibs and outright dishonesty. If getting caught in a lie wouldn't have serious consequences, it's usually okay to stretch the truth.