this is complex so I hope I can explain it – with impaled arms if the husband marries twice the femme side of the arms is divided again to show the PATERNAL arms of the first wife and then the arms of the second wife. This is how wiki describes it:
When a husband has been married more than once, the sinister half of femme is split per fess, that is to say horizontally in half, with the paternal arms of the first wife shown in chief and those of the second wife in base. The sinister side may thus be divided more than twice in similar fashion where required.
IF Megsy had arms which were “Markle” arms then Harry upon divorce would in his joint arms have to display her arms too as per above. But because she has no “Markle” arms or paternal arms Harry won’t in his impaled arms upon a second marriage have to display the Markle arms too. Or so it appears to me since she does not have paternal arms.
So the current situation appears to prevent Harry from having Markle in his impaled arms forever and his second wife from having to share her impaled arms with Markle.
Interesting. Thanks for sending this in!