What does FM mean??

'Forum Mail'. It's sort of like email - the button is at the top (next to 'My Account'). It's so you can email personal things to other people (and vice versa) without having to post it for everyone to see.

To that end, though, what do DH and ETA mean? I got the rest of them but I can't figure those out. I know DH is when you're married but I can't figure out what D is. And I know ETA is when people update their posts but I can't figure out what that is either.

DH means Dear Husband, Darling Husband (and sometimes, Dumb Husband! LOL!)

ETA means 'edited to add' .. Its when someone edits their original post to add more info

FH = Future Husband
FI - Fiance