Suicide due to other misfortunes?

I am twenty years old a college student and everything’s going well in my life, I have a good boyfriend, im attractive, i consider myself to be intelligent etc. my life is very good. Others in my life are not going so well my best friend’s baby’s dad has cheated on her with multiple girls; basically everyone I know has got cheated on or is being cheated on. I do not want to get cheated on and be hurt, due to this I have had recurrent thoughts of suicide and have told no one as I don’t know how to explain to people that this worries me. My own boyfriend knows to some extent but still i worry. Is it possible to kill yourself over something that hasn’t happened yet what’s wrong with me are all people like this?