Accepting changes that were made

[Lathriel]

Essex I do the same thing as you do. Besides what better excuse to re-read the book?

As for the beginning of the demise of Boromir, I see it clearly when they climb mount Cahadras. When he picks up the ring I think the process has begun. However, the journey through Moria delays the process because his mind is forced to be busy with other things.
Might I add that the part where Boromor picks uo the ring (whole climbing Cahadras) is an extra scene in the movie and yet I find it one of the most powerful scenes in the fellowship because it doesn't just show Boromir's uncanny interest in the ring;he voices the questions that might be playing around in the viewers minds during the movie.