If he had known Penny better and if, by the time he'd known her, he wasn't already so invested emotionally that he's blind to her faults, he would never have considered her as a viable partner in the first place

Unfortunately, many terrible love stories follow a similar pattern; initiated on insufficient information, and by the time information is found out such that, had it been known previously, the relationship wouldn't have been initiated in the first place, a biochemical version of the Sunken Cost Fallacy sets in.

"Influence, Science And Practice" is one hell of a book.