Cherry, I don't know how old you are so maybe what you are thinking is a good idea...I mean to get to know other men. However, if you this this man as much as you say you do and if you feel he is your soul mate and you want to marry him, I don't understand why you don't start the love part of your relationship. If you have been friends with him for so many years you know each other very well. I think the ideal relationship would be to be in love with your best friend.
If you both feel the same, try it out. If he feels the same way you do those feelings do not happen often.
Good Luck