what to do/need advice

Okay. My boyfriend confessed to me that he had a sexual experiment with a guy before, it lasted for a month. He told me it was just a sexual thing in college. He assured me that he's not gay. But honestly, I'm shock. I still don't know what to feel. I love him. I really do. But that information is really very shocking. I didn't expect that from him. I still do love him. But.. I just want an advice. How to deal with this.