Believe it or not, my husband's nickname is Poop. Not by me, but a long time nickname given to him in high school. His last name has a syllable in it that sounds like "Pee" and his mature high school friends used to replace it with Poop. Then, it stuck. He is 34 years old, and will run into an old high shool friend, who yells across the public place, "Hey POOOOOP!"
Most of the time I call my husband "Swee". Not sweetie-Swee.
My husband calls me Ames Jo (pronounced AMOS).
It all started about 9 years ago. There was a department store named AMES, and it was pronounced AIMS. My husband kept pronouncing it AMOS, and when he realized it bothered me, he started calling me AMOS, but spelling it AMES on notes, etc.
The Jo part came from the fact that everyone always assumes my middle name is Jo (it's not) because my first name commonly goes with Jo as a middle name. I am always having to tell people my middle name is NOT Jo. So, my husband, being the irritator that he is, started the nickname.
He writes it Ames Jo, but pronounces it AMOS JO. He has bothered me for almot 10 years now with this nickname. Even my Valentine's Day cards and holiday presents are addressed to the nickname.