A sudden increase in work or other obligations may be a sign that they are using these excuses to cover up their affair.
A sudden desire for space or distance may be a sign that they are withdrawing emotionally to focus on their matter at hand.
Cheating can cause a lot of stress and anxiety, so if they seem more stressed than usual, that could be a sign.
Gaslighting or downplaying your concerns can be a way to deflect suspicion from their case.
This may be a way for them to justify their infidelity or to distance themselves emotionally from you.
Cheating can be emotionally and physically exhausting, so they may use fatigue as an excuse.
If they're vague about their plans or aren't telling you who they're with, it could be a sign of cheating.
A sudden decrease in sexual intimacy can be a sign of an affair.
Frequent or unexplained trips for work may be a way of hiding their affair.