...Michael was right to leave her..After all he's been through with the senate hearings and Fredo's betrayal, where does she get the nerve to break Michael like that?

Micheal was right to remove his family out of his life. I guess Tom is the only survival. If I was Michael I would be angry at everyone after everything he's done to keep the family business alive. His character is truly tragic..

You're right, his character is tragic. But the reason why I believe so is different from yours.
Before they married, Michael had promised Kay that he will abandon the criminal life. And he had a lot of opportunities to leave. Michael had changed a lot compared to that summer day back in 1945 when he told Kay the Luca Brasi story and summed it up: "That's my family, it's not me."
Michael's tragic in "The Godfather" is that the love for his family blinds him and pulls him into the "olive oil" (read: "murder") business. He believes he'd have to kill the heads of the 5 families plus Moe Green plus Carlo plus a lot of innocent people (Tattaglia's whore was probably not the only one). He could have sold the business, lose the political and criminal ties before his father died, but he would have risked to lose his father's respect.
Michael's tragic in "The Godfathe 2" is that he confuses more and more "family" and "family business", which by the time of young Vito wasn't such a big difference. But his greed, his mistrust in others ate his heart. He believed he fought for his family, but he never really cared about them. His family relations reflect a lot of what was going on at that time: Men coming back from work, providing money, but they don't spend time with their families. He has to ask Tom what present he had bought for Anthony. He wasn't able to talk to Kay anymore. In one scene he's talking to his mother and asks her whether a man can fight for his family and by doing so losing the family. She doesn't understand. If he had loved Kay, he would have listened. He would have abandoned the gambling industry, he would have abandoned the New York ties to Frankie, he wouldn't play cat & mouse with Roth.
And if he had listened to her, he wouldn't be the lonely man he became by the end of GF2.

Tril, he's tragic because he's a murderer, a scum piece of humanity who deserved all the pain and agony he endured in III (although, there again, he did it at the cost of someone else's life). He died alone ... as he lived.

Olivant,

With attitudes as one-sided as that, I really wonder why you like the Godfather movies at all! Although Michael arguably did go too far at times (particularly with the prostitute in Part II, if it was he who ordered that), he was operating in a context where at least some of the violence was necessary. What was he supposed to do, be some kind of pacifist?!

I thought it was Kay who left Michael, not the other way around.

Honestly, I didn't like Kay that much. While she certainly wasn't a villain, I thought she should have shown more common sense. She knew she was marrying someone who lived in a violent world. It wasn't as if Michael was still telling her he had nothing to do with the Mafia when he saw her again after returning from Sicily. Given that, I don't think it was fair how she did her "J'accuse" of Michael in Part II. Yes, what happened was absolutely harrowing. Kay came very close to being killed. But so did Michael. Kay made no effort to see things from Michael's perspective, dismissing the whole world he lived in as "this Sicilian thing." It's true that he had told her that "in five years, the Corleone family is going to be compltely legitimate." But she should have had enough sense to be skeptical of that. Even aside from the possibility that Michael was flat out lying to her, doesn't basic logic dictate that making a major Mafia family completely legitimate in that short a time would be very difficult?

I don't think Michael believed he'd have to kill "a lot of innocent people." The only clear case of someone innocent being killed in Part I was the prostitute with Tattaglia, and as I've said before, I don't think Michael actually ordered her to be killed, I think Rocco and the other man with him decided to do it on the spot.

In the movie, it seemed to me that Michael needed Kay, but Kay (athough she still might have loved him in her heart) didn't need him at that point, or at least had given up hope of marrying him. Michael took advantage of Kay by lying to her. He told her in New Hampshire that "my father's way of doing things is through," and that "the Corleone family will be completely legitimate in five years." Whether he really intended it or not, it didn't work out that way--because Michael couldn't let go of the power, money and control he achieved through the criminal life.

In II, when they're dancing, she reminds him that the five years had already passed. "I'm trying," he feebly replies. The shooting that night, "in my bedroom...where my wife sleeps...where my children play with their toys" was provoked by his continued involvement in the criminal life. The look on Kay's face after the shooting when she's holding the kids said it all.

Near the opening of III, Michael attempts a shouting justification of his life: "I spent my LIFE...protecting my family from the horrors of this world." Yeah, sure, Michael--like machine gun bullets flying around your bedroom? Kay's reply--"But you became my horror"--was perfect.

There's a bit of resignation on Kay's part in III when she arrives in Sicily. She notes that Michael still has Al Neri around and Michael jokes that he needs Neri to help him carry his briefcase, and Kay takes this with a sort of wink and nod.
Her tolerance is short lived however. When they are at Don Tomassino's house proclaiming their everlasting love, they are interrupted and given the news that the Don was mordered and that vengence must be taken. She has this look of resignation...as if to say, "This will go on forever." Little did she know her daughter would be one of the victims.

I would love to hear the dialogue between Mike and Kay after Mary's death.

I completely agree with this! Much of the intrigue of GF, GFII and to a degree, GFIII is the complete metamorphasis of Michael Corleone and ALL the circumstances that led to it, gradually, over the course of several years. While he is certainly not a sympathic character by the end of GFII, those who claim to love the movies and yet refer to him as 'monster', 'cold-blooded', 'scum', etc. either fail or do not wish to truly comprehend what happened to him, and how the actions of OTHERS around him, led him to some of the decision he had to make.

Many of these same people praise Vito up & down, who while leading a far more violent life in his own youth (and was ready to kill a bandleader for not releasing his godson from a contract)...apparently had a better way with people.

And that's true...Michael did NOT leave Kay; she attempted to leave him which he was not about to allow. Until she admitted to aborting his child at which point he pretty much kicked her out (which she DID deserve, including the doorslam for not leaving in time for him not to have to see her).

Apple

In his confession in III, Michael said, "I betrayed my wife..." I thought that was a pretty good summary of what he did to Kay.

the book and the film, to me, indicate that Mike loved what Kay represented more than Kay herself.

w.a.s.p. Kay....the all american wife...instant assimilation...

Michael's certainly much more sympathetic than Betty Broderick, the San Diego woman who killed her ex-husband and his new wife out of jealousy (they were sleeping in their bed when she broke in and killed them). To this day, she sits in prison whining that she was the real victim, not them. Unbelievably, she has a huge number of fans, mainly bitter women who've never grown up.