I don't, and I'm not talking about Facebook, corporate or government agencies.
My girlfriend goes through my phone and messages, whether I'm there or not.
It doesn't bother me. I suppose she does it for peace of mind. Some of my best friends are girls and I'll often stay with them over weekends when she's working.
She might be stepping up surveillance though.
The GFs best friend has just rumbled her cheating husband, barely 15 months after getting married.
Suspicion was aroused by him suddenly not leaving his phone about. When he finally did, during a trip to the bog, she investigated and the lies unraveled.
So, do your other halves investigate what you're up to? Are they open about it, or do you just suspect that they do?