"AITA for yelling at my BF's sister for ruining my bridesmaid dress?"

I (26F) and my boyfriend Mike (27M) have been together for 4 years and living together for 2 of those years. Backstory, Mike his sister Kate (26F) and mom (51F) unfortunately lost their dad to a car crash 6 years ago. It was very hard for them. Mike and his mom channeled their grief with working out and his sister channeled her grief with eating.

Before you think I’m being rude, his sister is way over 400lbs. She has health issues and trouble walking “long” periods. When we try to help her, she tells us we are exaggerating and trying to project our own insecurities onto her.

I’ve always been on the thinner side, wearing xs/s clothing. I workout, eat healthy but of course have plenty of cheat days. I would also like to mention Mike’s mom will sometimes borrow my sweatshirts. And one day when I came home from work (a month ago) Kate was in our room with a pile of ripped clothes next to her. She said since I’m letting her mom borrow clothes I had to do the same for her.

(She only borrows my sweatshirts) I was upset she came over unannounced and ruined my clothing. She told me the clothing was poor quality and she wasn’t the reason they ripped. I told her she wasn’t allowed to borrow my clothes and couldn’t just come over whenever. She was mad for a few days but eventually got over it and things got back to normal.

My best friend is getting married in a week in Hawaii. Mike and I are going early and we leave for Hawaii in 3 days. Last night we had Kate and his mom over for dinner. Everything was going great and Kate excused herself to the bathroom. She was gone for a while so I decided to go and check on her. I found her in our room holding my bridesmaid dress that was ripped in half.

When she saw me she said I really need to stop buying such poor quality clothing. I was so mad, the wedding is in a week and my dress was ruined. I looked at her and started yelling. I told her we weren’t the same size and to stop thinking we are and that she needs to realize she’s not healthy and needs help. She started crying, pushed past me and drove home.

Mike and his mom heard everything and told me I had every right to be upset and that what she did was not okay. The next morning I got a ton of calls and texts from Mike and Kate’s grandparents and their aunts (dads parents and sisters) telling me i’m a complete AH for yelling at Kate and making her cry.

They told me I’m an insecure brat and it’s a good thing their dad wasn’t with us anymore because he would be ashamed Mike was with me. I was hurt, I always wished I could meet him and never expected to hear that from his family. I’m now starting to think I am the AH for yelling at Kate so, AITA?

What do you think? AITA? This is what top commenters had to say:

[deleted] said:

NTA. Kate could be 100 pounds and it is NEVER right to just grab people's clothes. And a bridesmaid dress? No, she's doing it deliberately. No one that heavy, and I am heavy, would think they were a small. She owes you for every article of clothing she ruined. She needs therapy. And she needs to pay for the fixing of that dress. Now.

Restin_in_Pizza said:

Is she cutting or tearing them on purpose? Because I've tried to fit into too small clothing, not THAT too small, but they don't just rip in half. NTA it clearly was an occasion dress and she probably did it on purpose out of jealousy.

OP responded:

The dress is a thinner material so It’s no surprise she ripped it when trying to put it on. Not sure what she told her family but they’ve always enabled her because she is suffering from the loss of her best friend. Mike and his mom have tried to help her but every-time she lashes out.

Accurate-Ad-4905 said:

NTA, Kate is 26, not 13. She knows your clothes aren't her size. I mean I understand some people can have body dismorphia but she would have bought heaps of clothes and knows she's not an extra small.

I don't know what her motivation for doing this is and don't want to speculate but it's not okay for her to destroy all your clothes or even try them on without asking. I hope your boyfriend and his mother called up the grandparents and aunt and told them the whole story, they owe you an apology.

Sweettart2017 said:

NTA. She is acting unreasonable, borrowing your clothes when you specifically told her not to and going into your room and closet without permission. Is your boyfriend defending you from her flying monkeys? Because if not, you may need to reassess your relationship

And OP responded:

He is, he’s blocked his grandparents and aunts after finding out what they said and refuses to see them until they apologize. Also, He’s been telling Kate she needs help but every time he does she’s lashes out. His dads side of the family enables her and says it’s because she lost her best friend.

She later added these updates to the post:

Edit 1: I did think I should clarify some things:

1.) Mike and his mom are super supportive of me and my reaction. They both have reached out to explain what happened but are being shunned and told off for not agreeing with Kate. Mike now has most of them blocked and refuses to see or talk to them until they apologize.

2.) I’ve seen a lot of comments about Kate likely just ripping my clothes. I’ll be honest, I didn’t see her actually trying my clothes and dress on. She told me she tried them on. She probably did just rip them and refuses to tell the truth.

3.) My friend is aware of the situation and we are both trying to find a replacement dress. Thankfully I didn’t have any alterations done so we are just trying to find the same dress and color.

4.) I gave Kate the benefit of the doubt before because I care a lot about her. I shouldn’t have let it slide and maybe we wouldn’t be in this situation.

Edit 2: after reading more comments, I will be taking photos and getting prices of all my clothing ruined and sending it to her. If she refuses to pay I will take further action. Everyone telling me to do that is definitely making me feel better. I know I’ll get hate from the family but it needs to happen. I’m also trying to get Kate the help she needs. Any suggestions? She will not go willingly.