The reason no one ever questions the weirdness is Riri can alter memories.
Anzu never considered she could just play along and DUMP the boyfriend she picked. Riri was to only ensure she became a couple with someone; not that they stayed together.
The premise is horrifying when you think about it. Anzu is being forced to fall in love; it's all manipulation, as she wouldn't seek out love herself. Making matters WORSE? She's forced into a cliche heroine status by having her family move to another country, Anzu cannot have real joy as her games were taken away; plus she can't even touch her favorite snack chocolate. So Anzu is being conditioned to be desperate.