It's supposed to be a bit of sarcasm. Kind of like "And then my Dear husband forgot to close the gate again and we spent the day rounding up the horses."
It also often means Damn Husband.
Hence the abbreviations.
However it seems used more often now...and for those who get sick of typing, DH or DD is a universally understood abbreviation but H or D and nobody would know what those meant. The context of the post lets the reader know whether the typer just meant husband or daughter but added the "D" so others know what they meant, whether the typer meant Dear or Darling as sarcastic/witty or whether they meant that "D" to mean Damn.
And for some of us...our family actually is quite dear to us.
At least sometimes they are.
You jump in the saddle,
Hold onto the bridle!
Jump in the line!
This discussion reminds me of something one of my guy friends said about his girlfriend. He told me she nicknamed him Xero. He told me it was because just by changing the pronunciation she could either refer to him as a "Hero" or as a "Zero".
I don't like the abbreviations either. If I want to refer to a certain person I just spell out who it is.
it's nice to safe some typing when the story is threatening to draw into epic lengths.
many times the Dears aren't tho dear...but hey. It's somewhat neutral.
And by now a commonly accepted COTH abbreviation, like SO (which means something completely different for non COTHers) BO (same here) or BM.
Heck, even GM means something other than the 3/4 god of the arena.
I use the DH to mean Dear Husband with no sarcasm at all. Doesn't bother me a bit. Re-home, re-purpose, whatever are fine as well. I see languages as constantly evolving, so those terms don't drive me crazy. Now text-speak, that sends me right up the wall!