This morning, to my girlfriend. Like many above, I tell her every day. I'm determined that, if tragedy strikes her, I will NOT be one of those people who wishes they'd said it once more. I also say it to my parents, but outside that, no. Tried it once, in a less serious sense to a girl who said it to me in a friendly sort of way, and it came out sounding waaaaaaaaaay different than how I'd intended. So I don't do that any more. Not like it led to tragedy or anything, it was just kinda awkward for a minute.