Dating My Brother’s Best Friend

So, my brother’s best friend and I have a serious thing for one another. We want to pursue a relationship, but we want to handle it delicately, we both know the consequences if it wouldn’t work out. These consequences include, he and I not being friends anymore, and we don’t want that to happen because he really is my BEST FRIEND, and we don’t want my brother to be upset. My brother and I are extremely close. Has anyone been in this position, how did you handle it, and did it work out????