Aftermath is defined as "a consequence, especially of a disaster or misfortune" and / or "a period of time following a disastrous event." Infidelity is definitely a disastrous event. The aftermath of the infidelity can leave the person that was cheated on with a plethora of feelings. They can range from asking "why", not understanding, blaming themselves, and of course hurt and pain. The important thing to remember is that YOU are not the one that broke the bonds of the relationship. Regardless of what you may or may not have done, the choice to cheat was ultimately made by your partner. You will go through a period of hurting. Let yourself go through the grieving process. You may never get the answers that you seek or that you need. You may never know why or understand. But the most important thing you can do is try not to let it affect your self-esteem. Realize that you were disrespected by the cheater, and you are better than to allow that behavior.
The choice to cheat is the result of issues your partner has - not you. It can be caused by insecurity, childhood issues, past relationships, etc. But generally, it is due to something lacking within them and not you. Many times it has absolutely nothing to do with you or anything you have done. As hard as it may be, get up and dust yourself off, realize your value and worth, and know that you deserve better. You deserve to be respected and appreciated.