My husband lies about having college degrees: Advice?

My husband now retired has always said that he has a masters degree from OSU along with a bachelor’s degree. I have never seen these diplomas. When his parents were deceased, I asked his sister to find the documents among the files at the house, and she looked at me funny—red flag. I contacted the schools in question, and he actually flunked out after one semester, which explains why he was drafted. I reached out to his ex-wife, and she confirmed it. She also said he would get very angry when she asked him why he lies about it. He continues even now tells our friends entire false stories about his grad school professors. I actually have advanced degrees, which I earned. I confronted him, and he was angry and said I was lying and the schools were lying. Why can’t he admit to this after all these years?