My stbDH has confessed he doesn't like his nickname! In fairness, I call him loads of slightly embarrassing nicknames (from the acceptable, like sweetie, through to the questionable sanity, like pookie and schnookums if I'm that way out). But I normally call him one nickname when I'm feeling a bit soppy. His real name starts with a vowel, so if his name was Ian, I call him mIan - it's come about as a contracted form of "my Ian" (he's not called Ian). I think it's sorta sweet!
His thoughts are it sounds like I wanted to give him a nickname but couldn't be bothered to come up with a proper one so just used a sloppy form of his name.
What about you? Embarrassing nicknames??