Whom should i marry boyfriend or friend?

I am having a boyfriend for last two years. We love each other a lot. Now six months before a new boy came to my life. He became a very good friend of mine. We talked for whole day and night on phone. Even after knowing about my boyfriend, he fell in deep love with me. He loves me so much that i have no words to explain. For him, i am his life. He says he will not marry any other girl except me. On seeing his love, now i am also in love with him. I cant live without talking with him. We both like each other company so much. Now i am in a very difficult situation. My boyfriend knows everything. He also loves me a lot. My heart says i should marry this new friend as i like his company so much. I feel so happy with him. My brain says i should not deceive my boyfriend and should marry him. What should i do?