My ex-husband (non-alcoholic, just a garden variety jerk) violated my privacy in a big way by putting a keylogger on my computer while he was living at our house and on a shared network. The only way I could stop him ws to cancel our internet and go to a portable internet with a modem that was for my computer only.
When he confronted me with the "evidence" of my so-called infidelity, I flipped, I freaked out and had never felt so violated or so angry at anyone.
Along with the so-called evidence, he got into my bank accounts along with my mom's as he thought I was hiding money from him in order to decrease what I had to pay out to him in a divorce.
Since then, I have been in a lockdown mode, using high security settings not just on my computer but on any shared network. I have a master password for my internet browser, sweep my computer regularly with SpyBot and Comodo, both free security programs. You can never be too safe or careful and even though we are divorced, I will never take internet security for granted.