Why does everyone stand up for my girlfriend (including me) but never me?

So I did one very small thing and it was I was late to a event she had and everyone chewed my ear off and told my girlfriend she can do better and that I’m not good enough for her, that she’s too pretty for me etc, but she cheated on me 5 times, lies, manipulates and uses me for my money and no one said anything or stood up for me. Why could that be?
Why does everyone stand up for my girlfriend (including me) but never me?
Post Opinion