I was surprised by how good this was, too. I would have liked some more melodrama and throbbing music (I'm such a romantic) pushed into the last few scenes, but European directors from that period don't ladel the (manipulative) emotion on in that way, like we do here in the U.S.
I didn't know anything about the plot, as I was watching it for Jennifer O'Neill's performance, but I thought the story was very interesting, and kept me thinking.
It was also VERY unusual to see a male character from the 1800's not freak out/be devastated by some marital twists and turns. Usually these stuffed shirts cast their spouse from the ancestral home, calling them a damnable whore, etc., and I really lose interest in the story, thinking, "Oh please, Mary. Take an asprin."