Almost everybody has a different definition of what constitutes cheating.

For some, having an intimate emotional connection with someone of the opposite sex is cheating.

For others, it may entail having close physical contact beyond normal friendship.

Nobody likes to be cheated on, but sometimes things that are out of control happen to us. What is important when such things arise is to become aware of what is going on, so that we are not hit by the repercussions of our partner’s decisions or actions while being blindsided.

This short PDF containing 99 common signs that your partner is having an affair does not claim to be a textbook – the list is non exhaustive, and yet at the same time, having some of these tell-tale signs does not necessarily mean that your partner is cheating on you.

It is important that you exercise your own judgement when it comes to reading these signs, and to not take things out of context. After all, you would understand your partner better than we do.

What is being shared here is the cumulation of more than 30 years of experience in being a Private Investigator, and we have dealt with investigating cheating cases since 1990.

We hope that what is shared in this PDF will help someone to stop their marriage from falling apart in time, or find out about a partner’s cheating before it is too late.

Commercial Investigations (CPIS) LLP



1. He sleeps with his hand phone by his side.
2. He brings his hand phone into the bathroom, often for long periods of time.
3. He has more than one SIM card.
4. He has more than one hand phone.
5. Your calls to his hand phone are unanswered, and he doesn’t tell you why or gives you an excuse that is not convincing.
6. His hand phone is switched off whenever you call him.
7. He tells you that you can call him at another hand phone number.
8. His hand phone is equipped with multi-SIM/duo SIM card.
9. He deletes the messages from his hand phone, or locks his apps/phone with a PIN that he does not want to let you know.
10. Intimate messages in his hand phone that were not sent by you.
11. He clears the call logs from his hand phone.
12. His hand phone bill is unusually high compared to the past for no reason.

13. He sneaks out of the house for no apparent reason and no explanation, especially at night.
14. He goes to the coffee shop for a drink but comes back 3 hours later.
15. Change of behaviour.
16. Change of attitude towards you.
17. Your instinct tells you something is not right.
18. Whispering or speaking softly on the phone, or does not take phone calls in front of you.
19. Hangs up the phone whenever you are near him, or walks away when you approach him while he is on a call.
20. You answer his hand phone in his absence and the caller hung up.
21. You answer his hand phone in his absence and the caller asked for a different person.
22. Loss of interest in family activities and becomes withdrawn.
23. Not wanting to air his view in plans related to the family.
24. Suddenly becomes particular about his looks.
25. Changes his dressing or style, and often looks at the mirror before leaving home.
26. Small intimate gifts in his possession that were not given by you.
27. Extra credit cards that you were unaware of.
28. Purchases of items in credit card statements that were not meant for you.

29. Credit card statements sent to another address.
30. Receipts of items not purchased for you found on him.
31. Extra money that were not accounted for and being stashed away.
32. His clothing smell of unfamiliar perfume.
33. The seat belt of his car smells of unfamiliar perfume.
34. Strands of hairs not belonging to you found on his clothing.
35. Strands of hairs not belonging to you found in his car.
36. Pubic hairs or random stains found on his car seat.
37. Lipstick marks on his clothing.
38. Unexplained marks or bruises on his neck/body.
39. Goes overseas more frequently than before.
40. Not letting you know his flight details when travelling.
41. Not letting you know the hotel he stays when overseas.
42. Coming back from overseas with gifts such as perfume claiming that it is purchased on behalf of his friend.
43. He spends more time on the computer especially in your absence.
44. He deletes details from his computer including emptying the recycle bin.
45. He shows sudden interest in music.
46. He joins a gym out of a sudden.
47. He walks the dog for extended periods of time.
48. Suddenly interested in jogging.

49. He finds reasons to stop wearing his wedding ring.
50. He buys himself sexy underwear.
51. He washes his underwear whilst having his shower.
52. He comes home in a pair of fresh underwear.
53. He leaves home fresh in the morning and comes home fresh in the evening.
54. He makes decisions without discussing with you.
55. He criticizes your appearance.
56. He criticizes your dressing.
57. He becomes impatient with you.
58. He becomes impatient with the children.
59. His friends/colleagues appeared uncomfortable in your presence.
60. He appeared uncomfortable in the presence of your friends/colleagues.
61. Prevents attending functions when your friends whom he knows are also attending.
62. He picks fights out of trivial matters.
63. He works late too frequently.
64. He entertains too frequently.

65. He criticizes your cooking.
66. He finds reasons not to have dinner with you.
67. He takes leave without your knowledge.
68. He stops telling you of his activities as he used to be.
69. Keeps condoms in his car/wallet when he does not use them with you.
70. Wants to try new techniques/positions when having sex with you.
71. Lessens the frequency of having sex with you.
72. Stops having sex with you.
73. Tries to go to bed after you have fallen asleep (to avoid having sex).
74. Giving prior notice that he is tired before going to bed.
75. Removes child seat/toys from his car.
76. Asks you questions pertaining to likings of women.
77. Asks you questions like “is it possible to love more than one person”
78. Hinted that it is all right to have a mistress.
79. Shows extreme concern about where you are when he is out without you.
80. Suddenly becomes calculative in the family’s expenses.
81. Accounts with banks unknown to you.
82. Daydreaming when he is with you.
83. Tends to be forgetful even on important issues.
84. Prevents fetching you in his car, or not wanting to be fetched by you.
85. Disappearance during family gatherings claiming to be going back to work.
86. Hotel receipts in his possession.
87. Hotel name cards in his possession.
88. Petrol station receipts that were not the usual stations he visits.
89. Treating you extremely nicely, to the extent that you feel he has done something wrong.
90. Telling you he is with a particular person to cover the time of his disappearance unaccounted for.

91. Does not hold your hand in the public like he used to.
92. Coming home wearing a different shirt from what he left home in.
93. Shows interest in items meant for females whilst shopping with you.
94. Goes to toilet too frequently when he is out with you, sometimes for a long time.
95. His secretary addressed you wrongly too frequently when you call him.
96. Unpaid parking fines sent to your house at somewhere he has no reason to be (especially after office hours).
97. Going for National Service (ICTs) too frequently, especially if he does not contact you during these “trainings”.
98. Background noise of phone calls does not sound where he claims to be at.
99. He feels uncomfortable when being introduced to a friend who is a “P.I.”, “investigator” or “Private Eye”.