You

I just realize why she couldn't ever say yes.

It's because somehow it would make an end isn't it ? Your world would stop turning. Everything that is you, somehow would change. The problem is, whether you would like the change or not. I guess your action is the answer that you've found. Probably you're scared, very-very scared, that why you weren't able to believe. And I think you're probably right :)

It's such a shame that we weren't meant for each other :)