Boyfriend lets his heart rule his head

I love my bf very very much but I get frustrated because he lets his heart rule his head. He gets VERY passionate and dedicated to his beliefs, and I love that, but it makes arguments/discussions with him extremely difficult because he absolutely refuses to see things with an open mind. I always try to see both sides and then formulate my decision or opinions. He doesn't ever take the time to try and see the other side because he's just so blinded by his emotional dedication. I try to tell him to open his mind a little, and he says he will, but nothing has changed thus far. I guess I should just be patient.. but it's so hard.