Realms of Fantasy
Given earlier posts, if an abdication requires an act of parliament, then it would be phrased in a way that suits the peculiar circumstances.
When King Edward VIII abdicated, the need was to ensure any children he might produce later did not come back into the equation. If Charles abdicated, a similar act would be drafted to suit his peculiar circumstances to ensure that the succession was determined in advance. (There is still the thorny issue of - can't spell - 'primo geniter' to get a female of the line to succeed).
The other issue is that if the Queen lives to a very grand age and (say) Camilla was unwell, Charles might 'disclaim' before he gets to be king. Presumably, that also requires an act of parliament.
Anyway: let's just wish Prince William and Miss Middleton a happy and contented life together.
O-D