Woman Gives Her Sister-in-Law a Harsh Taste of Her Own Medicine When It’s Finally Her Turn to Get Married

Me and my husband, let’s say his name is Michael, have been in a relationship for years. I knew from early on that Michael had a habit of financially supporting his mom and his half‑sister Karen in ways that struck me as extreme (for example: Karen asked him for a nose job as a Christmas gift). I sensed there was something unequal and off in their family dynamic, so I voiced concern.
Fast forward: when Michael and I got engaged, I began to feel intense jealousy and hostility from Karen (and some passive behaviour from his mom). Karen made negative remarks about me, tried to talk Michael out of marrying me, and throughout our wedding planning she acted super detached, ignored key traditions (she wore black despite being asked not to), and never showed real support. My wedding became more about her drama than our joy.
Now, Karen is getting married. She has given us virtually nothing (gift, support) and expects us to host her bachelorette party in our home and foot the bill. So I’ve decided: for her wedding day, I’ll “act like nothing’s happening” — minimal engagement, no special hosting or gifting. My husband agrees. The question: Am I the asshole for not giving her special treatment on her big day even though she didn’t treat me right on mine?

The claws came out in the run-up to her wedding, with her SIL treating it as a non-event

Now the tables have turned and she’s planning to beat her at her own game

The emotional dynamics & fairness question

You’re hurt. You invested in your wedding (as most people do) and expected family to care or at least behave respectfully. Instead, you got jealousy, passive aggression, silence, disrespect (e.g., wearing black when you asked not to), lack of engagement and even insults from Karen. That builds resentment.
When someone has treated you dismissively, it’s human to feel: Why should I go out of my way for them? You’re choosing to match her level of investment (or lack thereof). This isn’t about “tit for tat” as much as boundary‑setting: you’re saying you won’t be the only one extending goodwill when none is reciprocated.

Wedding & gift etiquette: what do norms say?

According to wedding etiquette sources:

• If you’re invited to a wedding (and able to attend), giving a gift is polite but the amount and nature depend on your relationship to the couple. The Knot+2Brides+2
• The presence of guests counts for a lot; the “free meal” mentality is shifting. On Reddit some guests argue that if you’re going to attend you should at least send a card or small gift, but rigorous expectation is fading. Reddit
• Modern etiquette emphasizes doing what you can and what makes sense for your relationship with the couple. Vogue+1
  What this suggests: There’s no formal obligation for you to lavish time, money or emotional energy on someone who didn’t show that to you. Your decision to scale back isn’t obviously “against etiquette” — rather, you’re opting out of extra effort because you feel it hasn’t been earned.

Boundary‑setting and emotional labour

When one person in a family consistently demands attention, resources or special treatment, and refuses to offer basic respect or support in return, it creates imbalance. You’ve described Karen as expecting gifts, freebies (living in the father’s rental, using streams, etc), and making passive attacks (e.g., shoulder comments about your family money, etc.).
By choosing to give nothing extra (rather than “punish”), you’re drawing a line: “I will engage minimally because you gave minimal.” Sometimes that’s the healthiest response rather than continuing to extend goodwill to someone who uses it for leverage. It’s also a way to preserve your emotional energy and reduce wedding‑related stress.

Could there be downsides / is there risk you’re being the asshole?

Yes. A few potential issues:

• From an external perspective, weddings are high‑emotion events. Some might view “acting like nothing’s happening” as cold or passive‑aggressive rather than gracious. The audience (other family/friends) might see it as refusing to be supportive of a sibling‑in‑law’s special day.
• If you choose zero engagement (no card, no well‑wishes), you might be seen as hostile rather than simply boundary‑set. There’s a difference between being cordial and giving entirely nothing.
• If hosting the bachelorette or contributing is not in your capacity (emotionally, financially, time‑wise), then refusing is fine. But if your decision is purely retaliatory, you might regret how it impacts wider family relationships later on (e.g., your husband’s connection to his family, future gatherings).
• Lastly, if your husband feels strongly that you should do something, and you ignore him, that could cause internal conflict within your marriage.

What the “treating her the way she treated you” means

Your phrase “the same treatment” communicates a mirroring: Because she ignored you, you will ignore her. Because she demanded gifts, you will not provide. Because she expected attention and you didn’t feel welcome, you will withhold.
Mirroring is understandable, but it’s worth asking: Is your goal to get even, or to protect your well‑being? The more you frame it as “I won’t be used for drama” rather than “I’ll make her feel what I felt,” the more powerfully boundaries become about self‑respect, not revenge.

Practical suggestions & legal/relationship precedents

• Communication: If you haven’t already, consider telling Michael and maybe his mother (if appropriate) what you expect — for example “We’ll attend your wedding but we won’t host or pay for parties that weren’t offered to us.” That sets clarity and might reduce last‑minute pressure (like the bachelorette at your house).
• Selective participation: You might choose to attend the wedding ceremony/reception and bring a modest gift (or none, as you feel) simply because you want to show civility, but skip events (like the bachelorette) that feel one‑sided.
• Emotional detachment: Mentally prepare that others (family, wider circle) might interpret your behaviour as “unfriendly.” If you’re okay with that, fine. If not, consider balancing a minimal gesture (card, simple gift) with your low‑investment boundary.
• Long‑term view: Family dynamics often shift. Today’s coldness may come back to you later (for weddings, kids, family events). Ensuring your husband is aligned with your approach helps because he’ll encounter his family too.
• Avoid escalation: Nothing says you need to match jerk‑for‑jerk. Staying graceful can serve you better. Instead of “no gift and no participation,” you might opt for “I’ll send a card, won’t host, won’t pay extra.” That keeps you above reproach.
• Therapeutic lens: Consider why you felt hurt and what you need. Maybe the wound is less about the bachelorette or the black dress, and more about feeling rejected. Acknowledging that can help you act from strength rather than pure reaction.

“Sis makes zero effort”: the woman provided quite a lot more info when prompted by netizens

In my view: NO, you are not automatically the asshole for deciding not to do extra for Karen. The expectation of equality, respect, gratitude in relationships is real. If you didn’t get it, you’re allowed to protect yourself.
However: you could become the asshole if you handle it with malice or passive‑aggression instead of setting boundaries calmly and respectfully. If you say things like “I’m doing this because you hurt me” in a spiteful way, or you gauge everything to punish her publicly, that moves toward asshole‑territory.
So: tread the line between self‑respect and mean‑spiritedness. If you stay honest, modest, and clear about your boundaries — you’re fine. If it becomes about “getting back at her,” you might regret it.