I really liked the "twist" where the toxic yuri happened before the current relationship, and it was causing problems with the present relationship. Sort of an examination of the lasting damage a toxic relationship can cause.
I felt so bad for Irina, she's clearly trying so hard and Seraphine's problem isn't even her...though maybe that makes Irina a little bit obsessed in her own way, too! Especially once you learn everything she knows. It's interesting how hard it can be sometimes to tell the difference between forgiving someone for their faults and turning a blind eye to them.