"[I tell Miranda], 'I have nothing to hide from you,' " says "The Voice" judge.
Shelton says that he even encourages her to check his cell phone if she wants to: "That's always been our policy: 'Here's my phone. Go through it.'"
"That's really the kind of trust we have," Shelton continues. "There are no secrets. [I'll say,] 'Go dig through my drawers or my computer if you feel like you need to.' And that's been a really good thing, because I don't want her to ever have any doubts."
The 36-year-old's denial comes after the singer was accused of having a month-long affair with 23-year-old singer, Cady Groves.
Lambert, for her part, told Us magazine in April that "Divorce is not an option" and that she ultimately “trusts [Shelton]… but knows how flirty he appears.”