Nova, I'm afraid it might be time for a new bf.
My MIL will never admit that she is wrong, and can take it to hysterical extremes to avoid saying she's sorry. DH will from time to time show that he is his mother's son, and I remind him that he is being like his mom (he does detest how his mom acts). After 20 years, I am slowly getting through to DH that if he can just say "I'm sorry", we can move on. Fortunately these moments are few and far between. However, for Nova, if it's affecting your relationship now while you are dating, it might be a sign to move on. Would you really want to put up with the "I'm never wrong" behavior always and forever?