She always puts herself down, seeking validation

Since we mentioned low self-esteem, this can also be a warning sign and a cheating characteristic to be careful of if you are already thinking she may be cheating on you. Generally speaking, if she always seems to be seeking validation, more so than the normal amounts (since we all want to be validated and it is normal to want recognition from time to time), Ladies who cheat end up needing constant validation, and they end up resorting to cheating to make themselves feel seen and worth it.

It can be because of her own mental health issues, but it is also a sign that she no longer finds fulfillment in her current relationship, so she is seeking the validation she craves in other partners. It does not excuse her actions, but to her, it may be the only way in which she can feel worth something, and her current partner is no longer enough for her in that department. Soon after something like this happens, it can also happen that she will seem more and more distant.