Naples? spoilers

It wasn't so much what he did in Naples as what he learnt. His son, his daughter, and Bellino - whose society persona was more or less created by him, or at least generated by him - all had a warped view of life that they had based on his way of life. Casanova thought that he was celebratng life and women, just being an amusing tearaway, but he came to realise that the rest of the world saw him as a debaucher, finding sensual pleasure wherever he could and not caring about the consequences. In turn, those who looked up to him became more and more depraved, thinking that they were following his lifestyle, to a point at which they were committing acts that he found abhorrent, such as incest. In fact, Bellino pointed out that she had the life that he should have had - implying that *he* could very easily have turned out that way too. Casanova couldn't live with the idea that that was how the world saw him, or that he probably had lots of other illegitimate children all living out their twisted idea of his life philosophy, so he disappeared.

Hope that makes sense and helps :)