What a good story, Michael!
We are often blind to what is in front of us, and when we are lucky, we find out before it is too late.
Well done, you are so good at this!

5/5 Ingrid ((hugs))

Sometimes in life we so blinded that we can't see what is in front of us. Enjoyed reading and great job.

Okay Michael, aside from this being and absolutely brilliant piece (and one I can't believe I haven't read) I will give you, as asked, my "help/opinion" on the flow that you think is off. Excuse the crude way it is done, but I'll just run through the bits that stood out from a rhythmic point of view.

I think the first two stanzas are superb, nothing wrong with the flow there.
In stanza three, it starts brilliantly (I love the idea of the 9 "shuffling up" in the pack - a brilliant play on words.
"Help was needed for his dream to play out
help to win her kiss, those lips that pout". - this stumbles a bit for me. Perhaps drop the kiss? "Help to win those lips, that pout" - not sure, but there seems to be a couple too many syllables there, in my opinion. Maybe you disagree?
"So he told the ten of hearts of his plan" - perhaps leave the "of" out? For me, that too would flow a little neater.
Stanza 4 flows fine to me - and you just scrape the nearly rhyme with "need" and "marry" - but it works. Personally, I love making use of almost rhyming words sometimes as it shows a willingness to discard pure rhyme for quality, which can be lost in rhyming poetry sometimes.
Stanza 5 is great until the last two lines - again, for me anyway. Those two just don't quite flow or rhyme enough in a poem that rhymes and flows so well up to this point. A
suggestion: "Help you, he said, to marry the Queen - rather, I should help you awake from this dream!" - something like that anyway.

Love stanza 6 - the flow, the introduction of a "female card" who is offering help when those above him - the higher and mightier - would not. One starts to suspect here.

Again, 7 and 8 flow well and we now know she cares enough for the nine that she wants his pain to "vanish" (love the strawberries and cream bit, by the way).

9 and 10, reading through, are superb - I love the last couplet in stanza 10 - they flow beautifully.

11 is excellent, but the last couplet in 12 I tripped a bit on. Maybe "Would shuffling now be to his advantage" - its one of those where really you need half a syllable!

Michael, stanza 13 is superb and maybe my favourite - the revelation of a growing respect/romance for the 8 of hearts and delivered with lovely vocabulary: "To miss before him a card who delighted" - wonderful.

love 14 - maybe in 15 "Her love for him, as true as the sky" would roll a little better than "truer than the sky"?

I love 16 but "he knew instantaneously" seems a little long? What about "He knew at once?"
Scrub the above. This is how I would write it: A rainbow arched across the blue -
Then he knew at once his real mews:
His full hearted neighbour - the eight all along!
She was the rhythm, the beat to his song!

Mind you, I do love an exclamation mark!!!

The last stanza (17 I think) is brilliant and finishes what truly is a wonderful piece and God only knows how this didn't earn you another WIN badge!

Michael? Michael? oh....you're asleep.

All the best then,
Ben