What was the 'ending' in the novel on which this movie was based?

WARNING: CONTAINS SPOILERS

At the very beginning of the movie, it is mentioned that on 24 June, 1940 Sir Rabindranath Tagore said: "EVER SINCE 'CHOKHER BALI' WAS PUBLISHED, I HAVE ALWAYS REGRETTED THE ENDING. I OUGHT TO BE CENSURED FOR IT."

What I want to know is whether the ending of the novel was different than that shown in the movie? If it was different and you know what was it, will you please let me know too?

One more thing. What do you feel was the reason that Aishwarya Rai leaves Kashi and goes somewhere else in the end instead of marrying Behari? Behari was ready to accept her, then why did she leave him while she too wished to be his life partner? Doesn't that sound rather strange and, all the more, illogical? I know that she's shown to be different and bolder than other characters in the movie, but this doesn't fit as a reasonable reason for her to leave Behari. Don't you feel there should have been some clarification, some explanation about the awkward decision taken by her?