This was really a tragic case. I think this guy had lived a lie so long he couldn't stand the thought of having to come clean. I agree; I don't buy the insanity plea either. This fellow had been way too meticulous in carrying all of this out, and the roots of it had gone back way too long.
This case also illustrates something important, especially to young women: If someone you are in a relationship with is not honest with you about their background, you really are not in a relationship with the person -- you're in a relationship with a ficticious character. My youngest sister is in her mid-twenties and a single parent. She started bringing a fellow to family events and introducing him as her fiance. The man claimed to be a former DPS officer, a drug enforcement agent, who had supposedly quit his job to spend more time with his kids. Several things in this guy's story didn't add up, and my husband and I were suspicious. Later, other family members started having the same suspicions.
Turns out this fellow was a high school drop out, who had been fired from a pipe line crew. He completely lied about everything in his background, including how many times he had been married. My sister, being of brilliant intellect, continued seeing this creep long after his story came out. She never could understand why the rest of us didn't embrace the creep with open arms. Only after several months and a lost job from a drug screening did she sharpen up and realize this man was no good. In the meantime, she took care of him and supported him financially.
Ladies, (and gentlemen) , please be careful out there. If you are serious about someone, use some common sense, talk to their friends and family. If they don't have any, that in itself should be a warning. If something doesn't ring true, call a halt until you find out the whole story. This isn't an isolated case. It happens more than any of us might think.