Mami is Mami. I don't really know what else to say about that, but I think she's one of the more interesting elements of the story.

At this point it's pretty clear what her motivation and character are.

Because of her incident in middle school, she's bitter. She doesn't believe love is real, and seeks to destroy it because she feels that it's fake, only an act, and it pisses her off.

She got with Kazuya on a whim, and broke up with him because he said the exact same thing to her that the boy that got her pregnant did.

This is ultimately why she arrived at the conclusion that she did about Kazuya, and offered to "save" Chizuru. If she views the boy that got her pregnant as a liar, who gave her false hope, and ruined her in a way. Then she sees Kazuya the same way.

This is obviously her coping from the trauma of being seperated by force from the person she loved, who's child she was carrying and that she wanted to have. (and let's be honest, probably got aborted).

Given that it's coping, and it's likely that deep down she either still hopes things would have worked out with the boy she loved, or maybe part of her at some point hoped that Kazuya would be the one to keep that promise (probably after Chizuru told her if she ever considered that Kazuya could be the one to make her happy.), and told her that it wasn't too late to reevaluate her feelings at the end of the previous arc.

I feel like Mami is going to make a realistic effort to try to get Kazuya back. Of course it will be too little too late. I can also see an arc where Kazuya helps Mami get out of her arranged marriage somehow, possibly with Chizuru's help.

Maybe even a possible reunion for Mami and Tarou-kun (that name still cracks me up a bit, Tarou is a nickname for cockroaches btw).

If not, ironically enough, she might be the one to challenge Chizuru the most or come closest to pulling on Kazuya's heart strings but ultimately fail (unless the author plans on giving us the Domestic Girlfriend special).

I think this also fit with the current themes because one of the things that Chizuru will have to deal with to be with Kazuya is the fact that she pushed Ruka and Kazuya together. but there is another girl that Chizuru pushed toward Kazuya, and that's Mami. She's gonna have to deal with that.

TL:DR What do you think is Mami's next play?