Do not violate someone's privacy. It's not just that it's a shitty thing to do (because it is), but it will end up driving you crazy. It won't help solve things, it will put you more at odds with each other and, more importantly, yourself. Even in my case- I had a boyfriend who was involved in illegal activities and it was important for me to know that he was putting my house in danger. I snooped but all I received was a crappy feeling, even though I was right. So what if I was right? You don't want to be big brother and cyber/tech sleuthing is not a replacement from good boundaries and honesty in a relationship. If you are at the point of having to look at their texts/facebook to find out important things, you are at the point where the relationship is broken beyond repair.