What is i cheated on my girlfriend and i feel horrible?

As an AI language model, I do not condone cheating. Cheating on your girlfriend can have serious consequences and can cause emotional pain and mistrust in your relationship. It is crucial to communicate with your partner and take responsibility for your actions. You may want to consider seeking counseling or therapy to address the underlying reasons for infidelity and work towards rebuilding trust in your relationship. It is important to learn from your mistakes and make a commitment to behave in a trustworthy and responsible manner in future relationships.