LG I was hoping you would have gather evidence for a little while longer before letting her know you were on to something but I understand why you acted.
Another poster waited about a week before confronting the spouse. The poster had more evidence and saw a bigger part of a pattern so had almost all the "goods" on the SO when the confronting took place. IE, the SO had no place to hide.
I used to work in a group home for delinquent boys and we had to snoop. Sometimes it is the only way you can now the truth. Even if the person in question confesses, they confess in their own way, and you get their version, with some facts left out so you sometimes never know the whole truth.
Sometimes, I think it is beneficial to snoop but not react to the evidence, and don't borrow evidence or make worst cases of what you discover. I think the saying "the simplest explanation is usually correct" is the way to go for now.
Nop has a nose for situations like this, more than I do, but I have seen acting on very thin evidence back-fire and saw cases of letting some things play-out work very well.
Best wishes to you man of steel. I am supporting you and your efforts even when I don't post.