It takes a lot to build a relationship, and when it comes down to a difficult phase, it is groundbreaking to continue it. Also, when you are blindfolded in love, you give too many benefits of doubts to your partner. Infidelity is a traumatic experience and difficult to move out from. Most of the time, it's the intuition we rely on and think if it's all in our head.  

While every relationship is different, and so will be the pattern of cheating- here are some early tell-tale signs that will lead you to find out the truth.  

1. When they get less accessible in the relationship and have weak explanations for it. 

In my personal experience, the early signs were increasing emotional distance and decreasing communication in general. More time unaccounted for than usual. With one partner it was an increase of suspicion of me, and with another, it was more of a pleading, tearful defensiveness whenever I tried to verbalize my suspicions.

                    - Familiar_Dream

2. When they are constantly accusing or getting suspicious because they are the one cheating. 

Being sneaky/defensive about social media and phones. If they hem and haw about adding you to SM, or try to control what you post and tag them in it’s a huge red flag they’re trying to appear single.

                    - Jilltro

3. When they are mysteriously disappearing or ghosting, this becomes a pattern.

If they suddenly start mentioning someone all the time. Everything reminds them of the object of their desire because they're constantly thinking about them and comparing you to them.

                    - trudytuder

4. Getting too conscious about the way they look! 

Changing their look: working out and being obsessed with looking attractive coupled with distancing themselves from you emotionally.

                    - gr8times5488

5. Listen up!

If they suddenly start taking a long time to reply to your texts and their responses are shorter than usual. When you meet up they don't seem excited to see you or engaged in conversation with you. If they talk about subjects they don't usually talk about. If their phone is quieter than it used to be (cuz they have the other person blocked or silenced while they're with you). If they start questioning you more or acting more possessive of you than usual when you've given no reason to. If you find yourself feeling suddenly insecure about their interest in you.

                    - rainb0wsprinkles

6. When they keep a regular check on your schedule daily. Like when are you heading home, what place are you going, and so on. 

Signs for me are text messages deleted immediately with the excuse they don't like to "clutter" the phone with too many. Protective of their phone and excuses to go help someone to the point of neglecting their own chores. Then the ultimate statement of "we're just friends and you're jealous".

                    - Natfreerider

7. When your gut feels something is wrong and your partner's actions confirm them. 

Always being busy with work, working late, or going out with friends all the time. Not picking up the phone or replying to texts like they normally would. Someone new suddenly likes all their social media posts. Someone who gives you a bad feeling.

                    - 5leeplessinvancouver

8. When the friends of your partner get uncomfortable around your presence.   

Not having enough time for you, making excuses just not to meet you , getting annoyed talking to you.

                    - Pomegranate00

9. When having communication about something turns into defensive bickering.

Distant, becoming defensive about certain questions, locking oneself in their rooms for days, lying.

                    - Demons_EnthusimQueen

10. To constantly argue and fight over petty things that don't matter. This becomes a pattern and you keep questioning what's wrong. 

Making arguments out of things they normally wouldn't bother with, or fabricating an issue to argue over.

                    - DixersDC

Some other changes include- differences in the pattern of intimacy, unreasonable spending, and emotional unavailability. 

Read more: 20 People Reveal The Dumbest Excuses Their Partner Gave For Cheating.