Originally Posted by
arguskos
As I see it, there are grades to such things (this assumes the relationship is meant to be an equal one; that of sub and dom, for instance, would have different tiers, as would liege and serf, etc).
At the top, as the worst things you can do in a relationship: severe betrayal of trust and willful action to hurt your other.
Next severe we have: accidental action to hurt your other and an inability/unwillingness to admit fault with mistakes and fix them.
Third we have: invasion of privacy (this is a breach of trust, but not to the same degree as meant above)
Finally we have everything else.
Note that I don't consider any of this minor, just that in the tree of things you shouldn't be doing, some things are more detrimental than others. If you willingly betray someone you love, it trumps everyone. It doesn't *justify* snooping through their email, but it would *explain* it. If they call you on it, turn it around and say "look, I regret having to do it, but I would never have if you hadn't betrayed me. Let's work this out, let's make this right. I'm at fault, you're at fault, but we can fix it. Let's fix this." If they don't agree to make things right and to work towards that fix, then get the hell out. They breached your trust, they are unwilling to admit their faults and work towards reconciliation, and they may well have done all this intentionally. It's over, leave now.
tl;dr: Sometimes snooping makes sense, as long as you admit it was morally murky to be doing.