when a soul mates

"I do love you, Dean" Castiel said in a calm tone, his caring eyes trying to meet Deans.
"No, Cas. You can't. I am forbidding you to do that. Love someone else, there are plenty of other people to love!"
"I don't care about them, like I do for you."
"Why don't you understand?! I can't- you deserve someone who can give you that. All of ... that. And it's not me." Dean said with a firm expression.
"That doesn't change anything about what I said being the truth. I never expected you to say it back. You should know that. I still don't, at all. I just want to be your friend, like we have been before. Your friendship is what I value the most in the world."
Dean mustered him silently, still very stiff and his grip tightly clutched the edge of the table behind him.
"So we just go back to normal?"
"That's all I want, Dean."

or

Dean doesn't understand his feelings for Cas at all and can't wrap his head around the fact that this isn't how you're suppose to feel for your best friend. Like the tingling sensation in his stomach when Cas smiles, the constant staring or the sparks that fly when they touch.