I find it really hard to believe that people do bad things and everyone calls me naive?

Like this guy I am dating lies a LOT and is terrible, but I just think he's lovely and make justifications. I would never lie or treat people badly and don't understand why some people do. People always call me naive and gullible. What is wrong with me. I have a lot of life experience, more than most people, but I am a little naive still. I don't know why.