Wanting to sleep with another man's wife is not necessarily evidentially equivalent to sleeping with another man's wife, as the reaction to Jimmy Carter's famous Playboy interview demonstrates. If Solomon updates his model of himself based on the latter but given only the former, he's already made a mistake.

On the other hand, your analysis would hold true if Solomon's desire for adultery implies a willingness to commit adultery given no causal disincentives, which isn't the same thing in the general sense but might be in this restricted motivational space. If that's true, Solomon's model of himself has already been updated based on his propensity for adultery, and conditioning on it would be double-counting the evidence.