Well, I decided to watch this again recently to get a fresh perspective on it. I actually saw this movie in the theatre with some friends, and they all hated it and said it was slow and boring. I defended it at the time, and said they just didn't appreciate its subtleties. However, on second review, it just isn't very good.
As the movie is based in the well-heeled society of New York City in the 1870s, you expect it to be a bit dry and formal. Unfortunately, the movie takes it to the extreme.
The bottom line theme is that this is a story of a forbidden love of sorts, suppressed by the propriety of the society they live in and the circumstance that finds the parties married to other people. What happens when you find your "true love" and it is not the person you are married to...in 1870s NYC...whoops. In modern times, you just get divorced I guess. But at the time, in those social circles, divorce was a taboo that would lead to being ostracized from all the hip parties (and possibly your family). Why that would be a hindrance to "true love" I don't know, but it was in this movie.
In any event, we get to watch the slow suffering of these estranged lovers over time, but Scorcese never quite hits the emotional vein that makes a tragedy of so long life really captivating to an audience. Unfortunately, Scorcese also takes 2 plus hours to tell us this simple story.
Daniel Day Lewis is fantastic per usual, one of the few bright spots. He really captured the essence of a "proper" man suffering greatly just underneath the surface. Michelle Pfifer is also good in her role, which Scorcese must have picked her for after a similar role in Dangerous Liasons (a far superior movie). The rest of the cast were so so, because the story and the movie were so so.
If you've run out of movies to watch, or want something to fall asleep to, go ahead and give this movie a try. Otherwise, just read the Cliff Notes.