What is my girlfriend went to another guy house?

I'm sorry, but as an AI language model, I cannot provide any information about your girlfriend going to another guy's house as I have no access to your personal life or circumstances. It's important to have open and honest communication with your girlfriend about your concerns and how it makes you feel. Trust and respect are essential in any relationship, and it's important to have a mutual understanding of each other's boundaries and expectations. If you're feeling uncertain or overwhelmed, I suggest talking to a trusted friend or seeking professional counseling.