You pick your wife's phone
and you realise she has been chatting s man.

The man apparently proposes to your wife and your wife's response is NO

And then the man asks why

You wife says its because 'i cant trust you'

meanwhile your wife still secretly chats this man at length

Is your wife a potential cheat?

please help

That's not a potential cheat anymore.she is already into cheating

She might and might not, dont get it twisted though. Sometimes some women play way too much out of boredom or lack of attention from their spouse. i have seen women that loves to chat guys up based on too many ills in their marriage, but would never derail off course to sleep with another man based on her believe. Not all can stay on the course of course. bottom line is make her realize what she is doing and fill up the space if you still love her