Why are the relationships so complicated?

Have you ever felt love for someone but everytime you interact with the person you want to kill yourself. This feeling is killing me. I think I should stop all interactions with her but at the same time stopping them will slowly kill me because it will destroy a relation I'm not ready to lose.

It's the one of the only person who ever cared for me and I care about her but continuing to interact is always hurting me.

Why is it so difficult? It must be because I have a crush on her but she told me before I even had the opportunity to tell her that she only see me as a friend so I know there is no hope so I know I should tell her the truth and maybe kill our relation but losing her will hurt me too much so I don't know what to do.

Leaving all alone is a dream, no one to care about, no one to think about before taking a decision and if you are in a situation without an escape you can always kill yourself without consequences.

Is what I am saying stupid or dangerous? Or is it a way of thinking that is acceptable? Is it a way to take life that deserve respect? Or should it be despised?