Just a quick sketch i've just thought of

INT.PUB

Two men are sitting at a table

MAN1:
TELL YOU WHAT, THAT LUCY PINDER, SHE'S SOMETHING SPECIAL HER

MAN2:
DUNNO, I'D SAY YOUR WIFE'S MORE SPECIAL THAN HER

MAN1:
YOU TAKEN THE PISS

MAN2:
NO SERIOUSLY, YOUR WIFES PRETTY SPECIAL

MAN1:
IN WHAT WAY'S MY WIFE SPECIAL

MAN2:
WELL, SHE HAS THE MENTAL AGE OF A 4 YEAR OLD

man1 starts nodding

MAN1:
YEAH, I SUPPOSE SHE IS PRETTY SPECIAL

END

Don't get it.

Man2 is sayin man1's wife has special needs, as oppose to the good special, being amazing.

I don't really think the premise is strong enough to be honest. There's nothing wrong with it apart from it's a bit weak.

Far to much premable for such a simple punchline.