1. All of their technology is password protected
Always look out for changes in behavior. If your spouse has always been a private person, then if they don't want to share their passwords, it's not really an indication of anything to suspect. But if they once were an open book and suddenly it's harder to break into their iPhone, it might be a strong sign they have something to hide, and most times its infidelity (other common reasons are often a financial secret, such as gambling or making a bad investment without telling your spouse).
2. They accuse you of cheating
While it may seem counterintuitive, people who cheat will often accuse their partner of cheating as a way of projecting their own guilt onto them. While these accusations are often a sign of guilt, it causes you to be on the defense and distracted from their actions. It is a manipulative move. Because they get so upset during the conversation you begin to think that they hate cheating and would never do it, when in reality, they might have done so already. Part of them may even hope you have cheated because it would alleviate their own guilt over cheating.
3. They're avoiding specific locations
Psychotherapist and marriage expert Laura F. Dabney says that if your spouse seems nervous or reluctant to go check a particular restaurant out or another public place, it may be because they often go to that establishment with their lovers and don't want the people that work there to recognize them with someone else.
4. They are changing their appearance
Certified counselor and dating coach Jonathan Bennett says “If your partner previously cared little about her appearance but has made big changes out of the blue—like buying new clothes or wearing makeup more often—it could indicate an effort to impress another person.” Of course, the same also applies to men who feel a sudden urge to dress better and beef up.
5. They take their cell phones everywhere
Sex therapist Dr. Damian Sendler says “It’s not difficult to imagine that cell phones harbor a wealth of information, including texts, videos, and e-mails. Hiding a cell phone or taking it to the bathroom or even on the shortest trip to take out the trash is a red flag. It means that the partner doesn’t want us to see something.”
6. They regularly go MIA
The classic excuse "Sorry my phone died, can only be used so many times."
7. They don't want you to do anything nice for them
If your spouse seems defensive or appears to be uncomfortable when you make a romantic gesture for them, like offering to cook for them, it might be a sign that your offer is making them feel more guilty because they know that they don't deserve it. Saying things like 'I'm a bad person' for no apparent reason, can be a sign that they feel guilty over infidelity.
8. They pick arguments
If your spouse appears to be more irritable lately, or they are yelling at you for pretty minor, or even unreasonable things, they may be trying to offset their own feelings of guilt by making you out to appear like the one causing problems. Someone who is cheating is feeling a lot of guilt. Which may cause your partner to take out this shame on you by making you feel bad about yourself.
9. They are traveling a lot more for work
If your partner always had a job that included a lot of travel, it doesn't necessarily mean that they are being unfaithful. However, the sad reality is that being away from home simply does offer more opportunities for infidelity. So, if they seem to be heading to the airport more than usual without a good reason, your suspicions are well-warranted.
10. You notice the same phone number crop up on your bills
Want to catch your partner in the act? Look at their monthly bill for their cellphone. If you notice the same unknown number appears several times, especially when you know they weren't around you, that is a huge red flag.
11. He's about t to hit a big milestone
A study conducted in 2014 found that men were more likely to look for an extramarital affair if they were about to hit a big milestone birthday. This is especially true for men approaching their 40th birthday.
12. They are liking a lot of photos posted by the same person
While it may seem harmless at the moment, reaching out to an ex on Facebook to catch up, or spending a lot of time on someone's profile, is considered to be a form of micro cheating, which experts say can erode trust and often lead to actual infidelity.
13. They mention the same person frequently
If your spouse seems to bring up a certain 'friend' over and over again, and you are getting a little jealous, they are liable to say that you are just being crazy and paranoid. But the truth is that bringing them up is a pretty clear indicator that they've got a certain someone on their mind.
14. They surprise you with gifts
Relationship expert Charlotte Rivers says “it’s commonly known that gift-giving is a way to butter someone up when you’re feeling guilty about something, So what could [they] be guilty of? Most likely: cheating.”
15. They're suddenly on their phones all the time
Alisha Powell, a clinical social worker who works with couples on marriage retreats says “There is a thrill that comes from being secretive and trying not to get caught. Cheating can create a relationship that has excitement and risk. It can indicate a break from the monotony of the relationship with one’s primary partner.” So if you notice your partner suddenly texting and smiling all the time, or checking their phones for messages several times a day is a huge red flag.