Winners always take responsibility, even when it was not their fault

You should always take responsibility, even if what happened was not your fault. People who are obsessed with appearances justify their failures by pointing to outside factors. Winners do not do that. Even if she cheated on you, there is almost certainly at least one thing you could have done differently that would have changed the outcome. Maybe you could have extended the relationship and ended it on your own terms earlier. Maybe you missed warning signs that were there all along. That falls back on you. That does not mean the cheating was your fault, there are many different factors at play, but there is always something you can improve. Do not tie your self-worth to how someone treated you.