How do you know, if you're deemed as significant, the way you uncontrollably and irreversibly your significant other half?

You make me so happy, yet you're capable of disabling the joy as effectively. And putting rights and well-deserves aside, I'm scared too. I've never been in a relationship like this one before and it's all foreign in the weirdest way. But yes, I'm really scared. Is it okay to be scared?