The author has endured years of disrespect and sabotage from her sister-in-law, culminating in a disastrous wedding experience. The sister-in-law's actions were deliberately hurtful and created a hostile environment. After a year of no contact and no remorse from the sister-in-law, it's understandable that the author and her husband would choose to protect their emotional well-being by not attending her wedding. The sister-in-law created this situation, and she should bear the consequences.
The author portrays herself as a victim, but her narrative is conveniently selective. She mentions upgrading her engagement ring around the same time as her SIL's engagement, potentially fueling the jealousy she claims to despise. Furthermore, while the author claims to be easygoing, her detailed recollection of every slight suggests a deep-seated resentment and a desire for validation. Skipping the wedding only escalates family drama and proves the author is just as petty as the sister-in-law she criticizes.
The sister-in-law's behavior during the wedding planning and on the wedding day was clearly inappropriate and disrespectful. Wearing white to the bridal shower and sabotaging the flower arrangements demonstrate a lack of consideration and an intent to undermine the author's special day. However, the author is not entirely blameless. While the sister-in-law's actions were egregious, the author's decision to cut off contact for a year without attempting any reconciliation also contributed to the current situation. While self-protection is valid, completely shutting down communication may not be the most mature approach. The sister-in-law clearly has issues, but the author must take some responsibility for the way the situation has escalated.