Discussion: Soulmates

Do you guys believe in soulmates?
And if yes, do you think the relationship between soulmates HAVE to be romantic?

I have a friend, well, now my best friend really, who is a guy.
We attended (we are graduating) the same class for 4 years at high school (we are now 18) and ever since the 1st grade everybody said that he liked me. We became friends instantly but we weren't really close, just had some things in common.
Well, we started to get to know each other more and more and everybody kept asking me whether I like him romantically because it was obvious to them that he had feelings for me. I told them I didn't, but I guess nobody believed me and they just kept 'shipping' us I guess.
Our story really started in 3rd grade when he suddenly confessed to me on a party. I was slightly drunk (I'm not sure about him) and we talked for hours. I apologised for not being able to return his feelings and we actually stayed friends because he said that even if we couldn't be together, he wanted to stay friends.
From that moment we ACTUALLY were honest with each other, like we literally told each other everything. Today he is the one who knows me the best and likewise I guess.

The reason why I'm asking this is that I cannot imagine my days without him, but I also know that I can't love him romantically.
So basically, I think he is my soulmate, but not romantically.

Question is: do you guys think that it's possible?