Network administrator spouse receives and reads my emails from his computer, how does he do this [closed]

My spouse set up a home network that links my computer laptop to the intranet via a home server that he installed and administrates. My computer skills are pretty much limited to online groups, searching the internet, plus sending and receiving emails. My controlling spouse knows where go, which sites I've searched on the Internet, plus he also receives and reads duplicates of all of my email communications by clicking on an "envelope" icon that's pinned to his taskbar.
I plan to move out of the house and need to know how many miles away will be far enough to prevent him from accessing and reading my personal emails. What business spyware should I look for on my Win 7 computer and my iPhone 10?POP3 is on my computer. Is that how he's remotely receiving duplicates of my emails? If so, should I disable that function, or is POP3 necessary?Also, assuming I am able to find any business spyware on my computer and cellphone, before having it removed, is there a way to preserve that information, just in case I might need to have this evidence at a later date?Thanks