<< 
On the bright side, you've made just about everybody who's entered this thread feel better about themselves.  I also find it extremely amusing how you refer to your in-laws as "out-laws" and "locusts". rofl  >>
I agree wholeheartedly.  You HAVE had a helluva week.  *pats you on the back in a reassuring, yet non-sexual way*  Everything is going to be OK.  I believe that everything happens for a reason.
Got news for 'ya; I found this out the hard way w/a girl I was ENGAGED to.  Any woman that you cook dinner for and put up with her family (locusts....

) and then she turns around and wants to split, is not worthy of you.  You can do better.
You didn't mention kids; as long as there's no kids involved, the divorce will be relatively easy and FINAL.
One thing, and please don't take offense.
I'm going to assume that you two are a youngish couple...say early to mid 20's?  Reason I say this is b/c your wife obviously went out that night with an immature friend, to a pickup place.  Most "older" ie. 30's and up, folks wouldn't do this b/c it's wrong (IMO)
You don't go to a meatmarket when you're not on the market.  Capisci?
This has always been and still is a pet-peeve with me, with some of the women I've dated.  Invariably, your potential new GF/wife has a slutty friend that likes to hang out in the meat market clubs.  Even though your wife may have absolutely no intention of cheating/fooling around, it's wrong and DANGEROUS for her to be there in the first place.
Even I, that have a very difficult time keeping the Beast Down Under, under wraps do not hang out in the singles bars.  It's disrespectful to your significant other.
My current GF had some slutty friends that she used to occasionally hang out with (at the start of our relationship...I put the kabosh on that crap QUICK)  After many arguements about her going out with THOSE particular women, my GF called me one night from the club they were at.
Apparently, her two drunk and drugged friends (my GF doesn't drink or do drugs though) picked up THREE drunk and drugged guys and told them that "heck yeah our friend is with it!"  Of course, my GF wasn't "with it" and didn't want to give some guy a BJ in the parking lot.  Well, they waited for her right outside the front door and wouldn't leave.
I had to go there and play "Tarzan to the Rescue."  She never went out with them again.
Sorry to go off there....I tend to get very yappy, very easily.  Your week is over.  Life goes on.  Nothing is ever "The End of the World."  Chin up.  You didn't get this far by being a softie.  You'll be fine.  
 
EDIT
I didn't see your post from today! 

  Sorry about that.  I see now that you have two kids.  That's the worst part about this entire situation.  I have a six-year-old son and am in a terrible situation with that...so I feel your pain.
It sounds like you have a good attitude about it though.  See if you can work it out with the wife.  However, if it doesn't work out, the no child support thing would be dandy.  Make sure your lawyer gets that in writing and it's concrete.
BTW, I also see you are 31.  No disrespect intended on the age thing.  Your wife should've known better. :|