Why does Diccte care?

Do you really? Perhaps you've never been in a similar situation?

There's a code among women (and men, too, though you don't hear about it so much) that you don't date your girl friends' exes. Personally, I think Dicte reacted like a spoilt little dog in the manger (ffs, she didn't want to get back with Torsten, and she's supposed to be in love with Bo, so what does it matter who gets with her ex?), but she, Anne, and Ida Marie must have respected the code, or Anne wouldn't feel so guilty, and Ida Marie wouldn't have slapped Anne. For me, I think that once you're past school age, the code doesn't really matter anymore – you're all adults; and in this case, Anne had known Torsten for a really long time anyway, I think for as long as Dicte had known him (as I recall, it was implied once that Dicte met Anne before she met Torsten), so Anne and Torsten have been friends for ages, and it's kind of natural for them to get together.

Upshot is, there is a code not to date exes, but Dicte really only cares because she's a self-absorbed kælling who makes everything about her.

"Less reality, more fantasy!"