“My god… they’re me… If anyone would know me, it’s the mare who married me, right? Of course! Then… WHO AM I!?”

Considering what Shining Armor this is his reaction is probably something like: “Why is there two of me?”

THAT SHINING IS A SPY

“Ok each of you gets one chance to prove you the real Shining and ready go.”  
“Cadance we’ve be though so much together, our love for each other defeated Chrysalis before and I know it will beat her again this time.”  
“I like corndogs.”  
“I knew it was you sweetie. GUARDS TAKE THIS FAKE TO THE DUNGEONS!”  
“WAIT NO CADANCE I’M THE REAL ONE PLUS WHAT THE HEY IS A CORNDOG ANYWAY I DON’T UNDERSTAND ANY OF THIS!”

@FanOfMostEverything  
Or maybe she’s getting back at him for his earlier errors. She and Chrysalis could have had girl talk and bonded over his stupidity.

It’s actually kind of comforting to know that they’re both that gullible.

“What the-!Oh No! An Imposter shining Armor!”  
“Wha-no Cadence it’s me! I’m your husband. Cant you tell that’s just Chrysalis with a rag on her head?”  
“(In a haughty masculine voice)I take offense to that bug.You can’t insult my wife by saying she would fall for such a cheap,lowly trick!”  
“Yeah tell him shiny!”  
“Cadence she is literally describing what is happening! She didn’t even cover her body! look! You can see her holes!”  
“(Haughty voice)Hey buddy it’s not nice to go telling ponies to go look at at other ponies holes.”  
“Only that evil ugly,smelly,Nasty OLD changeling queen would be so horrid. Right Shiney?”  
“…(man voice)Of course honey though I don’t think that Queen was that old.”  
“Celstia dammit!”

Such an improvement :)