It’s been weighing on your mind for some time. You can’t quite put your finger on it, but something just doesn’t feel right. Your relationship was going so well but somewhere along the way, it changed. Back in the hidden folds of your brain, the thought is born that perhaps your significant other may be cheating on you. You quickly dismiss such an absurd notion, as that’s something that happens to other people, not YOU. You’re too smart, too good-looking and too wonderful to be cheated on. Yet, you can’t help shirk that shadow lurking in your head. Without directly witnessing a betrayal, how can you tell if he or she is really cheating? Here are some behaviors to be on the lookout for:

1. There are long, unexplained absences of your significant other.

You try to piece together a chronology of events of a certain evening that your current flame went out without you and realize that there are gaping loopholes. When your significant other finally turns up, he or she is way too intoxicated to explain his / her whereabouts for the previous few hours.

2. They arrive home after 2 AM.

Even in the busiest cities in the world, there is usually nothing healthy or positive being done by your significant other after 2 AM without you. By that time, most restaurants and bars have shut down and the patrons have moved on to couple up privately or go home. If your guy or gal had a couple of drinks, he or she should ideally want to get back home to snuggle up with you. Repeatedly stumbling home in the late, late hours of the night means he or she has found something (or someone) better to do.

3. Secretive about phone.

Beware the significant other who protects his or her phone like a fortress. His or her phone goes off and before you can reach over to grab it for them, they have sprinted, hurdled a couch and whisked it away from you in a matter of milliseconds. When you ask who is calling, she smiles and says, “A friend.”

4. Suddenly very busy at odd hours.

Your significant other’s schedule used to be wide open, but out of nowhere, he or she is tied up with last minute plans or meetings that run hours past schedule. You could be ok with this, except the plans are happening at all hours and never include you.

5. Defensiveness.

You decide to go the honest route and ask straight up if your partner is cheating on you. Instead of getting a laugh and sincere assurances that this is not the case (along with plausible explanations of whatever has led you to believe such a thing), you are hit with insults of being nuts, of having too much time on your hands, of having no life yourself, of being jealous and paranoid. You’re now feeling humiliated AND insecure.

6. Your stealth work and intuition raise red flags.

He told you he was going to the local bar to meet some friends or that he was taking a weekend trip to a certain hotel. You pass by the bar and confirm he’s not there. You call the hotel and ask for his room, but there’s no guest by that name.

7. Odd credit card charges.

Uh-oh. You’re looking at his credit card bill? Bad sign. You see his unpaid credit card bill sitting on the counter, decide to open it and notice jewelry, flower and bed and breakfast charges. You realize your birthday and anniversary passed months ago and you didn’t receive any jewelry, flowers or weekend away.

8. Showers immediately upon coming home.

Like without passing go to say, “Hello.” No hug or kiss. He or she won’t respond to questions. You wonder why there’s a need to shower when nobody is going out anymore for the night. You’ll hear crazy excuses like a taxi driver with bad body odor, a bird crapping incident, a room of cigarette smokers, etc. You’re wondering if someone else’s body spray is being washed off along with other bodily fluids.

9. Frequently changes email account passwords and not because it’s recommended.

She’s constantly looking over her shoulder while checking her email. She immediately deletes all texts after receiving them.

10. You’re suddenly showered with gifts, flattery and unnecessary over-the-top gestures.

You’ve been feeling a bit distanced from your significant other lately. His frequent business trips and late nights at the office have taken a toll. But suddenly you’re receiving an expensive hand bag, chocolates and a day spa appointment – all paid for. You wonder if this last gift is to keep you occupied for a good chunk of the day. When you ask why you’re receiving these items, you’re told, “Just for being you.”

11. Checks out others; doesn’t try to hide it.

Every time you’re out with your significant other, he has a wandering eye. When you leave to go to the bathroom at a restaurant, you’ll often return to find him flirting with the hostess, server or an attractive woman at the table next to you.

12. A strange scent.

Her shirt smells like cologne. His sweater is covered in perfume and lipstick. They likely did not get attacked by ultra aggressive cosmetics employees at the local department store.

13. Slow to get back to you, can’t be reached.

You’re trying to reach your significant other. In this day and age, there is very little excuse for not responding to your significant other when they’ve been trying to reach you for a few hours. In the chance that a cell phone battery died, they could borrow someone’s phone, find a payphone or find a way to send a quick email. There are too many ways to be in touch when you want to be. Bottom line is this: if they don’t care to be in touch, they’re likely touching someone else.