Here's my concern...this is big-time blowout binge potential for your ex. He's about to start a new job, so he's probably anxious, he's been on vacation/drinking for a week, and he's no doubt telling himself that this Saturday is his last chance to really do it big AND he's been "good" about not drinking around your daughter, so he deserves this reward.
By all means go out tomorrow night and have a wonderful time...and it isn't right and it isn't fair, but maybe this particular Saturday isn't a good time to be that far away?