Yeah, once in a blue moon out 'till 10am, okay...as a fairly regular occurance? Yeah, there should be some red flags with this one. Spaz has some good advice, but just to follow it up...if you do confirm that she's having an affair, then don't do any more snooping...it will only make things worse for you. If the PI confirms that she's just partying with a group of friends 'till 10am every time she goes out with them, it's still obviously going to be a problem in the marriage and you will need to address it.In either case, you have to decide if her behavior is going to warrant going or staying. If you decide to stay, you should probably consider marriage counseling. It can work, but only if you BOTH put the effort into the work it will take. If one or the other isn't willing to do that, then it won't work. I'm sorry you're going through this. I wish you the best of luck with it all.