Think about this for a minute - are you OK with those types of conversations your W is having? You may never see the extent of it, but then again, you may discover something. Either way, even what you do know is inappropriate contact.
Her phone may be protected by fingerprint, but it can be accessed by a code (usually 4 digit), too. Just sayin...
There are moments in this life when you are so confident in the rightness of your actions, that not even for a second do you consider the option that you might be wrong.