You confide in him and you share with him all your secrets; he is always there for you when you need him; and then one day you realize that this is it... he is the one for whom you have waited so long. He knows and understands you, is there for you when you need him, and makes you smile.
You tell yourself that you love him and you are meant to be with him. But you are scared, you hesitate because you think you will lose him if he does not reciprocate your feelings. Letting your interest be known can either break or make the relationship.
The last thing you want is to reveal your feelings and lose a good friend. But you love him so much that you can't keep it to yourself, and you want more than a platonic relationship.
Before you know it, he also might realize that he loves you. And if he already has been secretly loving you, then this will give the two of you ample opportunity to share your feelings.
One thing that is dangerous when you are in love is to hide your feelings completely. Be frank and give him subtle hints. Approach your friend with the idea of dating. If you're both looking for someone, and you both already like each other as friends, then chances are you may make a great couple. But you have to take the first step and break the ice.
Don't break up with your own boyfriend just because you think that you love your best friend. It will be unfair to him. If you are not comfortable in the relationship, and it's in fact torturing then you can break up, but don't break up just because all of a sudden you feel that your friend is the man you have been waiting for so long.
Don't pursue your desire to make him love you if you feel that he treats you just like a friend and nothing more than that. Remember you can't make a relationship happen, or work, with one-sided affection. Thus cherish your friendship because a true friend is more valuable than anything you can find.