Have you ever found about about your SO's infidelity and pretended you didn't?

This question is NOT about why you would or why you did leave a partner who cheated on you. If you want to answer that question, there are already plenty of them.

This question is about not leaving an unfaithful partner and not even letting them know you know. There may be worse things than a partner who cheats on you. Or there may be overriding considerations that make it okay, or okay enough. There may be reasons for just letting it go.

If you caught your SO cheating and didn’t bring it up, why did you do that?

And if you haven’t done that, under what circumstances might you not confront your partner whom you caught cheating?