Whoa Jan! Make paragraphs next time. Or at least put smiley faces in... found myself reading the same line over and over.
Apollonia was boring. She also had a whiny ass voice, didn't know the days of the week in order, and couldn't drive worth shit. But she was SOOO pretty. DAMN HER. I hate her too. Bitch!
But since you read the book, you know that Michael DOES tell Kay he had been with someone else. She got a little mad, but come on. He's a man and men have one weakness: Their pee-pees.
Apollonia wouldn't have been a better wife because she was Italian. I'm sure she would have been just as annoying and bossy as Kay.

Mike by that point would have made his wife a prisioner whether she was Kay or not. Apollonia wasn't a pushover, you can tell by the way she wines and honks the fuckin' horn after Mike learns Sonny died. So considering Kay and Apollonia were both strong women, Mike would have been screwed with either one.
So in my opinion they're equal, except Kay could teach classes and sew ugly curtians, and Apollonia could cook and wreck cars.