Question: Having read a style guide recently, I was under the impression that you don't add commas after the ellipsis when the ellipsis indications pauses or thoughts trailing off, followed by "he says" or the like.

E.g.

"If only I had known..." she whispered.
"If I'd known, I would have never..." he says, his voice going quiet.

However, I've recently seen several novels which stick a comma after the ellipsis.
E.g. 

"If only I had known...," she whispered.

"If I'd known, I would have never...," he says, his voice going quiet.

Does anyone have an opinion about which is correct?

I also have a question about spaces before the ellipsis. I see books with and without the space and have heard different opinions on the subject.

Is this correct:

"If only I had known..." 

Or should it have been:

"If only I had known ..." 

Thank you for any advice.

Answer: 
The ellipsis **is** punctuation, representing a kind of pause, so it's redundant to add another punctuation mark. Think of other similar situations, such as where quoted speech ends with a **?** or **!**: a comma after either of those would be out of place.
It is a matter of personal preference. Nothing's written in stone. Styles change, and those who change them are called humans.

That said, an ellipsis immediately followed by a comma looks silly.