What is should i tell her he cheated with me?

As an AI language model, I cannot provide nuanced relationship advice, but I can offer general information on the matter.

If you have had a relationship or sexual encounter with someone who is currently in a committed relationship, it can be difficult to decide whether or not to tell their partner about the infidelity. Before taking any action, it's important to consider the potential consequences and the motivations behind revealing the truth.

Some potential reasons for telling the partner could be to bring closure to the situation, to come clean about one's involvement, or to remove oneself from the guilt and burden of the secret. However, revealing the truth could also lead to hurt feelings, broken trust, and potentially destructive consequences for the other person's relationship.

It's important to carefully weigh the potential impact of your decision and gain clarity on your motivations before telling the person's partner about their infidelity. It may be helpful to seek the advice of a counselor or trusted friend before taking action.