A direct quote from the Votemaster this morning:
Can someone enlighten me as to what it means? My wife suggested “ball” but that hardly seems so raw as to require asterisks.
Bone.
Blow, surely.
Blow for sure - It is an ancient meme to say the girlfriends give BJs; wives do not.
Could be ‘bang’ too but ‘blow’ conforms to a common joke form.
Yeah, you’re right.
Blow.
And uh…memes aren’t 100% reliable.
Blow.
There’s an ancient joke with the punchline, “and the bride said, ‘I just gave the last blowjob of my life.’”
I’ve also heard the joke that the difference between a wife and girlfriend is the GF swallows.
It can only be blow. Old, old joke.
All right, I feel dumb now.
Has anyone mentioned “blow”, yet? 
Heh. I haven’t heard “ball” in this sense in a long time. Other than that fact, it doesn’t make sense since, presumably, while times are a-changing, reproduction is still an important part of many/most marriages and that usually requires balling/boning/banging of some type, but not blowing.
Since the obviously correct answer has already been given, let’s move this to IMHO.
Colibri
General Questions Moderator
boss
I always heard the joke as:
Q: Why are brides always smiling?
A: They’ve given their last blowjob.
Q: what’s the difference between a job and a wife?
A: After twenty years, the job still sucks.
Who said this? Other than a blowjob, what the heck is this about?
Here’s the relevant context. It has to do with Farenthold.
Same vote here. And while I didn’t read the entire thread to see if someone else mentioned it, it brought to mind the old joke ------ What is the difference between a bad job and a new wife?
After a year the job still blows.