Well if he thinks it is sent to make trouble for his family I hope you hits the delete button. Wouldn't you do the same for your family?
I monitor my minor children's communications because I the mom and it's what my husband pays me the big bucks for (not).
I would expect my husband to have enough respect for my spiritual integrity and maturity as well as intellectual capacity to deem it unnecessry.
My wife is an adult and handles her own E-mail. My daughter is almost an adult -- 18 in less than 2 weeks -- and does the same. They're capable of handling anything that I'm not.... My wife probably more so than I, given her life experience, before we met. My son is 9 and gets guidance.
My husband and I check our teenage daughter's e-mail from time to time. I also sometimes check her web posts, just as a precaution, although she is quite discerning and lets me know if she has any interactions she finds uncomfortable. We trust her intentions, but not always her judgment.
My husband will sometimes look over my shoulder at FR and say, "HuH?" which is a signal that he'd like me to pay more attention to real life :-). And I will talk to him about any exchanges that disturb me.