In movies, there will never be a more mismatched couple than Roger and Jessica Rabbit.
Back to TV:
Drew Carey and every one of his girlfriends.
Ethel and Fred Mertz (he was old enough to be her father, and not exactly as prime a catch as Gary Cooper or Humphrey Bogart.)
Andy Sipowicz and – again – just about every one.
Barney Fife and Thelma Lou. Of course, there wasn’t a lot to choose from in Mayberry.
From Home Improvement, Al and Ilene, the orthodontist he dated. Waaaay out of his league.
Darren (either one) and Samantha of Bewitched.
A smart witch and a fumbling muggle?
Revisiting the age discrepancy, Holling & Shelly from Northern Exposure were (from the actor’s ages) 35 years apart. Cute couple, but still quite unusual for the TV landscape (as far as long-term relationships go).
Well, at least Roger was devoted to her. He may not have had the looks, but he did bring the love. Most sitcom husbands in this category are arseholes.
Lookswise, absolutely. I think George Costanza and every one of his girlfriends is a better example, though. He’s a pig as well as ugly.
Actually when she started packing on the (pregnancy) lbs, and he lost a few the roles sort of reversed. He’s not a bad looking guy at all so long as he’s not 100 lbs overweight. She does not carry excess weight well - at all.
On Northern Exposure, though, the age difference really was supposed to be accentuated, and made the relationship something much more interresting. Besides, Holling might have been old, but he was one hell of a guy, according to all the stories that got passed around on the show.
Certainly more fitting than Shelly Tambo and Maurice Minnefield!
Larry David’s wife, Cheryl, on Curb Your Enthusiasm. It is not that she is so hot, but he is such a tool that no-one would stay with him!
I loved Holland and Shelly together.
This thread has me trying to think of a reversed situation now, with a hot guy and a frumpy wife, and I’ll be damned if I can think of a single one…
They’re both homely and have extremely vanilla personalities. I thought they were a perfect match. She was the female version of him.
Herman and Lilly Munster. Talk about a mixed marriage! 
I dunno, I bought him with Sylvia. (Sylvia? The DA played by Sharon Lawrence.) The blonde he ended up with after I stopped watching the show, though – I don’t think so.
I haven’t noticed any cases of the husband way too hot for the wife…just like you never see 50-something females boinking 20-something men, etc. in the movies, but you sure see a lot of the reverse.
I was going to say Jerry, but you’re right. George is better.
That’s the one I was coming in to say. Plus, that mother-in-law drives me into a coughing-up-blood rage whenever she’s on screen. She deserves every Emmy she’s ever won.
Mmmmmmm, Penny Singleton…
Tobias and Lindsay of Arrested Development
Lindsay is a shallow materialistic rich girl and sometimes an activist poseur who gets by on her looks.
Tobias is just a clueless dork.
You know the whole slob/hottie thing used to bother me… Then I went to a wedding this weekend of some old high school friends.
All the gorgeous girls there had the dumpiest average looking husbands. All pudgy and plain looking. I was surprised.
So Courtney Thorne Smith and Jim Belushi? Not so far off from reality.
I happen to have watched the first few episodes just last weekend–Shelly was supposed to be eighteen years old, and Holling in his sixties.
Remington Steele. Major league Pierce Brosnan and the cute but strictly Single-A Stephanie Zimbalist.
Here’s to you Mrs. Robinson…
Another one from the movies: Clint Eastwood and Carol Channing in The First Travelling Saleslady.