Are human beings faithless by nature?

I have never known a human being, ever, who did not eventually betray my trust. Most people betray trusts on a regular basis, without even conscious thought. It has gotten to the point that I no longer form normal human relationships because I know that any trust given to a person will always be betrayed, and any confidences given will eventually be used as ammunition against me.

Many years ago, I owned by own marketing firm with a partner. I made more money than I ever had in my life. I did work which I regarded as below contempt, and in return people were eager to throw large amounts of money at me. In the getting of that money, I was required to do underhanded, sneaky, conniving, vicious, hurtful, malicious, evil things. What struck me most is each time I stuck the knife in, people didn’t really get upset. They didn’t react with outrage or defiance. They would give me a look of hurt, sometimes, but mostly just glum acceptance – evidence that they are cheated and betrayed on such a regular basis that they regard it as entirely normal and beyond any capacity for preventing. It’s as if betrayal of trust is an act of nature, like a tornado or tsunami, which falls on the just and the unjust, and must simply be accepted. My self-loathing at engaging in this behaviour eventually became so great that I quit, gave away everything I owned, and spent the next year homeless.

My question, then, is two-fold. Is humanity by its nature faithless? And secondly, if this is so, why is this faithlessness so existentially painful to me when it’s clearly just business as usual to everyone else? It’s especially puzzling, given that I experienced nothing but betrayal, deceit, and malice during my entire childhood, which would seemingly either prepare or inure me to future faithlessness.