That certainly goes to show that my argument that Michael was faithful for Kay's sake isn't very convincing unless the listener also believes that Michael truly loved Kay. And not everyone got a strong impression of that in the film the way I did.

But as far as Michael "settling" for Kay is concerned, I'd like to submit that the reason he was so reserved in his proposal to her is because he was tentative about giving his heart over to someone lest he lose that person again, the same way he lost Apollonia.
Well, what is a "thunderbolt" after all, but a hormonal phenomenon .

Seriously, I will concede that it's reasonable to believe that he loved BOTH women. I read this opinion on another film discussion board, so I am paraphrasing the writer. But he said that Michael, like most great characters in literature, film, etc., had a duality about him. Part of him was "old world" and loved Apollonia's youth and innocence; her old fashioned obedience; the way that he was her protector, provider, and teacher -- and also her authority figure.

But part of him was "new world," and I can see him wanting to share ideas with someone at his own level of education, and not a mere girl to whom he had to first teach English. He loved Kay's intelligence; her Americanism; her independent thinking; the things they had in common.

BTW, if Michael had been married to Apollonia and brought her to America, I don't think people would have any problem believing that he is faithful to her out of love... Or would there still be this attitude about Michael that he is only faithful to maintain control and not be caught in a weak moment?