desperately need spying help, keylogger etc.

I need help finding a totally invisible keylogger. I recently found a search for child porn on my computer and when I questioned my spouse he said he wasnt looking for children but porn of teens over 18. Obviously I need to know for sure that is sick scary stuff. The problem is we have a bunch of spyware zone alarm etc. on the computer and he is pretty computer savvy.Does any one know of an invisible keylogger that wont show up on the spyware and that is hidden in the files.
Thanks for your time