Normal structure for Dialogue paragraphs

Now I'm not sure whether this is something that's an accepted teaching with regards to structuring paragraphs, or just something that is commonly used...

I'm talking about paragraphs that are structured as follows:

"Quote," attribution, "continuance"

You see this throughout literature.

My question is, can I break this norm?

"Quote," attribution, "continuance," further explanation, "completion of quote."

Here's an example:

“Dawn once told me about a problem she once had with her step-mother." Wendy cast a furtive glance at Dawn, to check that she allowed Wendy to continue, "The one where she found her step-mother..." she reduced her volume considerably, "with someone who was not her father."

I've emboldened the narrative away from the quotation to illustrate what I mean.

Is this acceptable?
Granted, this is a fairly trivial example, but the the principle of what I'm asking remains.

Answer

You can insert narrative into dialogue wherever a speaker might pause:

"You," she finally looks at me, "have been," her finger touches me on the chest, "much too reckless with my heart." She pushes me away and stands. "Go!" She points at the door. "And don't come back."

Where the speaker pauses will depend not on syntactic rules but on what makes sense in your story. For me even this feels fine:

"You," she finally looks at me, "have been," her finger touches me on the chest, "much too reckless," she leans close, "with," kisses me, "my heart."

Interweaving the description and dialogue in this way makes sense because the behavior and the words flow in unison. You can imagine the speaker pausing for effect when her actions become increasingly contradictory to her words. Still, you might find a clear separation more sylistically elegant:

She finally looks at me and touches me on the chest "You have been much to reckless with my heart." She kisses me, then pushes me away and stands. "Go!"

That is of course not the same chain of events, and you might prefer words and action in parallel. But you must not overuse such a "special effect", because it soon becomes annoying to the reader, as any deviation from the usual.