when?

i do not know when i became such an untrusting person. when was the exact moment or was it an accumulation of a lifetime of misdeeds? 
i know i spend far too much time thinking about things and as often as it annoys me when people read into the things i say, i read into the things they do not say... the things they do and do not talk about...
i mistrust everyone. i try with all my might to think the better of you, but in the end i always think you are going to turn on me and ruin me. it is not just simple paranoia, it is a deep seated lack of faith in everyone. it is all encompassing and all consuming... 
i sit here and obsess about what someone is doing, when they are going to change their mind, turn on me, abandon me, leave me for dead... i am going to die alone in the wreckage of a deep betrayal that i should have seen coming...
i need to figure out how to stop this vicious cycle of mistrust... it ruins everything and will continue to for as long as i let it...
what if i could find the catalyst that began this all... the defining moment that set me on this path? would it help me understand? would it stop this never ending pattern?
i want to trust. 
i want to trust someone.