We have been together for a long time, over 15.5 years and there are times that I have used his cell and vice versa, but I don't have access to his email nor do I want it. He doesn't have access to mine, and gain nor does he want it. I agree with tickledpink, somethings are just private, and it has nothing to do with having anything to hide....that's just my opinion.
I think it's called mutual respect and honesty on both our parts. It's worked for a long time, so I'm sticking with that.