And why should she do that? What does she have to gain?
Trust me, things will go badly at some point and women act on emotions in the moment...maybe you want to cut it off and she doesn't want to, maybe she wants you to leave your wife to be with her, etc
Haven't you ever heard the saying
"Hell hath no fury like a woman scorned"?
Women can be extremely vindictive...even the ones who you never thought it possible that they could be like that. Sometimes, especially those ones.
If you don't know this by now I'm not sure what to tell you.
For your sake I hope your phone is locked down like Fort Knox, your wife doesn't know your passwords/pin code/have fingerprint access and that you prevent anything from showing while on a lock screen.
Imagine your wife picking up your phone and seeing a nude pic of her as an incoming message or other salacious message.