It was likely a threat to coerce Ioan into accepting her abusive behavior (she seemed to be upset based on context about him not approving of her abusive messages towards other people on Social media or the parking lot incident). My mom was pulling the same
tit on my father (they were both terrible btw), just to later tell me that "sometimes you have to push some buttons to get what you want"
I personally dont think that she knew that the marriage will end, she was convinced that Ioan will accept her abusive behavior just for the sake of the kids and his image. And the fact that he was pacifying her most of the time (which she is using as proof that Ioan loved her till the end LOL) will have made her more convinced of it.
While I'm sure Alice didnt love him for a very long time (maybe even never) I dont believe that she was shopping for a new boyfriend. Much as she sees him as a loser for her ego he was perfect (the combo of a mildly successful, well-liked, attractive, very patient and caring man is not that easy to find), until he started fighting back at least.