Is it normal to fall in love with you best friend?

I am a girl who is in love with her best friend of 14 years. We met when we were 12 and about 10 minutes later I knew I was in love with him. We 'dated' a little bit between the ages of 12-13 but nothing too serious and shortly after my parents found out I was not allowed to date him anymore. They refused to let me date until I was 16. Since then, I have moved away, moved back, we have both dated other people. We have been in serious relationships and all throughout we have been there for eachother as completely reliable friends. I know I can trust him with anything and I would be there for him no matter what. We have never so much as kissed all this time even though there has been an undeniable, intense, physical attraction. 6 years ago I met my husband and 4 years ago we wed. My best friend was my Maid of Honor so to speak. He stood up for me at my wedding. A few years ago we both came clean to eachother that we have been in love for all these years and we were both kicking ourselves in the butt for never acting on it. My entire family loves him (so does my husband) and it pains me to be around him. The attraction between us and my feelings have gotten so strong that the second he walks in the room my entire body aches for him. I can't imagine life without him - but I can imagine life without my husband. Is it normal? I should also mention my husband and I have two children who adore my best friend and he adores them. I am so confused on what to do here - I think too much of my friend to have a physical relationship with him while I'm married to someone else...but I can't bear the thought of never being with him.