psycho pooper: need advice!

I have a 7 year old beautiful Persian that I rescued from a shelter when she was 2. She is a wonderful cat in all regards, except one: She simply will not poop in the litter box.

For 5 years, I have been able to cope with this by teaching her to poop in isolated area. But recently I moved in with my fiancee and my cat is pooping all over her house.

Fiancee is ready to ring her little neck and wants her back to the shelter! Now, I have to make a choice. The girl or the cat! (just kidding). But seriously, this has become a huge mess.

There is nothing wrong physically with my kitty. Vet believes that her problem is due to anxiety. The theory is that as a kitten she probably had a bad litter box experience; most likely the poop became stuck and caught in her long hair. So, any attempt to go in the box brings up very bad memories, and she avoids it like a plague when pooping, although she pees in the box without hesitation. Psycho indeed.

In any case, PLEASE. If anyone has experienced a similar situation and knows a clever, creative way to convince kitty to go in the right place, I'd be incredibly grateful. It may even save my marriage!

2 litterboxes per cat, plus one.

A lot, and I mean A LOT of cats will not poop in the same box they pee in.
Try it.
Also try a feliway plugin or two.
If that fails, and you and your vet pursue the anxiety issue, a lot of times the anxiety can be dealt with chemically, but I'd go that route as a last resort.

A few more notes:

Fiancee also has a cat. 2 litter boxes already. I've tried 3 boxes, even tried an empty box, and a box with carpet. No luck.

Vet prescribed valium. I've been giving her 1/4 piece a night on and off for about a year. Helps with her anxiety but still no luck with poop in box.

What is a feliway plug in?

How much space do you have?

Please click here for some things to try to help stop inapropriate pooping.