Help me please!!

I'm going to try to make this as short as possible! Basically , my boyfriend of a year just told me he was bi . I had no idea ! Actually he didn't tell me, his friend told me. I confronted him and he said its true and I don't know how to feel about it . Knowing in his head he thinks I'm beautiful and he is thinking about other guys as well. What do I do please help me . I need all the opinions in the world right now