she really is obsesses with MC for whatever reasons. Maybe she regrets her choice back then. She will even confess to him in a future chapter, but as soon as he rejects her, she's fucking her ex. She thinks that MC still is in love with his ex-wife trying to save their relationship (as to now she doesn't know about cherry nurse). While thinking so, she is making plans to expose his ex-wife to make him see that ex-wife is no good for him so he will accept her. But I wonder, if she is so interested in him why would she immediately bang with her ex after being rejected by MC. If she really is into him, fighting for him wanting to be more than just sex friends (a real couple), then wouldn't she stop having sex with others for the time being? At least as long as she is fighting for him. This makes her look like a total whore.