Who can never be a real man?

I have just completed the novel and while I have a few questions, one pops into mind:

Why was it speculated by Tom and Michael that Vito held Fredo in disfavor because of "the old sandwich job", while he did not really appear that upset at Sonny regarding his affair with Lucy?

"The Don was straitlaced about sex. He would consider such cavorting by his son Freddie, two girls at a time, as degeneracy. Allowing himself to be physically humiliated by a man like Moe Greene would decrease respect for the Corleone family".

Was he more upset at Fredo because he let Moe Greene publicly slap him around?

Also, in the movie, when Vito is talking to Johnny Fontaine in the beginning he asks him if he spends time with his family. After JF says "yes", Sonny walks in (after his scene with Lucy against the door), Vito looks at him and says "Good, because a man who doesn't spend time with his family can never be a real man".

Sonny has no reaction to this, so I was wondering if he purposely said that as an indirect *hint* to Sonny, or was I just reading too much into that?

SK

No, I think you're totally correct about talking about Sonny also. He even looks right back at Sonny at the beginning of that line. And also at the Sollozzo meeting(possibly only in movie) after Sollozzo leaves Vito says to Sonny, "I think your brain is going soft from all the comedy you're playing with that girl." That was about him talking out of line while Vito was talking. I hope that's what you wanted

As Puzo said, the Don was notoriously straightlaced about sex. But I think the Don more or less tolerated infidelities in others as long as their behavior didn't cause more trouble. I think his disapproval of Fredo's sandwich-jobbing was more because it resulted in Moe Green slapping him around--if he had paid attention to business, the disgrace wouldn't have occurred. You bet he was directing the "real man" remark at Sonny as much as Johnny. But again, the real offense wasn't infidelity--it was if the infidelity resulted in neglecting family. Just before, the Don had asked Johnny, a notorious philanderer, if he spent time with his family. "Sure I do," said Johnny. "Good," said the Don--approvingly. The reproach to Sonny was because he'd left his wife and kids at the wedding table to bang Lucy.

Thanks DColletti for your insight and opinion on the subject!

Turnbull, thanks for the clarification, as I have noticed you're the one everyone seems to turn to.