I got the bug because I was afraid Greg was cheating on me. So...
Mandy Summers: I got the bug because I was afraid Greg was cheating on me.
Booth: So why didn't you mention this before?
Mandy Summers: We're not supposed to date. I guess it's not like the FBI. We're not allowed to sleep with someone we're working with.
Brennan: What- Is she talking about us?
Booth: We're not ...
Mandy Summers: Oh, it's okay. I'm CIA. My lips are sealed.