HFF, They hate it when you catch them in a lie, don't they? Actually I read somewhere that wasn't a good thing to do! But I've done it myself. I guess we all want to know if there is any chance they can be honest with us again.
Do you know how to clear your browser history? Doing that erases every site you've been to. How to do it varies with the computer/browser you use but you can find the info online. Make sure you clear your passwords, too.
I do this every time on on DB. My H knows that I 'get support' online but he has no idea what. I consider it my personal therapy so I don't want him to see. Plus, my D uses my laptop at home so I definitely keep it cleared for her sake!