Have you ever cheated? physically, emotionally, mentally?

hey,
i m curious to know if you have ever cheated on your bf/Gf and how ?
Do u regret it ?
what was the reason?
was that person you cheated with worth it ?
If you had a chance to "undo it" would you take that chance?
or
Have you been cheated on? and why?
would you give a second chance to the cheater?

Thank you!