Is pretty clear what happened.
She didn't find another good man after MC left her.
Don't know what rumors spread in the company, but MC have less spine than a worm so I'm betting he didn't tell anyone she cheated and she possibly only said they fell out of love or even that wa shis fault, after all she did say it was his fault she cheated, like the bitch she is.
She knows he is a good guy and wanted to fuck around, MC found out by chance, but nothing says that was her first time or she would have left him if didn't discover it.
She most likely lied to her parents too and brought up some stupid reason to MC leaving her, or maybe invented that they separated in armony.
Most likely her plan is using MC being a fucking pushover to lie in the parents meeting and say they are back together and will marry soon, betting on MC inability to say no to anyone, even in the face of absurdity,
Remember how he just took it on himself in the flashback and had to go through therapy after being cheated on, his willspirit is weaker than a bug.