Hi IDM, I know it must have hit you really hard seeing that I'm sorry
BUT, the KEY word in that is "speculated", now she could have been looking that up for anyone, right?? Family member, friend, friend of a friend.........and certainly if anyone looked into my computer (especially after being on PC ) then they could draw up hundreds/thousands of conclusions which would be mis-leading.
So maybe it was for someone/anyone else??!! And the fact that she deleted it.........well maybe it just didn't answer the questions she/they were looking to be answered, I know I've deleted plenty of things for that reason........or maybe it was just a "fleeting thought" and...........so slow down a little, hey??
And when you say you've never been a good husband........well chance that's the depression telling you a lot of that??? But if you do think there are some areas you can improve on well maybe that's just something to try and work on bit by bit???
But regardless........you know marriages/relationships do have up's and down's if.........but that seriously doesn't mean that they are necessarily lost..........so if you think have a talk to her about it, and there will be options after that if the marriage needs a little more "attention" from you both.

Alison