Responses
I think that he just like her in a non romantic way, like in a cute way or something like that. But maybe it's because the string himself cannot dictate actions, just like de scissors guy said, there are people who never know they fated pair but this doesn't mean that they will never be in love or something.
SPOILER
So the main character contradicted himself. He loves the girl friend but the strings aren't attached. Like why do you still like her if she isn't for you????