"He wasn't the man I thought he was" is a misjudgement by party A and doesn't seem at all equivalent to party B actively deceiving someone by pretending to be a

"He wasn't the man I thought he was" is a misjudgement by party A and doesn't seem at all equivalent to party B actively deceiving someone by pretending to be an entirely different person with a different name, back story, interests, profession and so on, and then having sex with them. It makes me feel queasy that anyone would think they're even in the same ballpark.