I have kept my best friend's secret that she cheated on her now husband when they were engaged in college
How did she cheat
She had sex with my ex-boyfriend for a couple of months.
It's okay to show loyalty to a friend. But you should encourage her to tell the truth. By supporting her, it's showing her that it's okay to cheat.
I wanted to help her.
It makes sense that you just want to be supportive, but people will think you're a bad person too for helping to keep their infidelity a secret.