Advice on Dealing with a Difficult Bride/sister!!

Ok, Ladies,

I need your unbiased opinions and advice on my current situation as MOH in my youngest sister’s upcoming wedding. I’ll be the first to admit, the entire wedding process is largely unfamiliar to me.

As a mother of three girls also, in the wedding 1BM and 2FG the cost of simply attending the wedding will be hundreds of dollars. In addition, I’ve done everything from dress shopping with her, giving her my veil and unused wedding decor, ordering the handmade FG dress from Etsy, buying the FG Keds shoes to match hers, agreeing to the additional expense of having our hair and makeup done, including the cost of hotel accommodations to stay with her the night before the wedding like she requested, among other things.
It all started, with my sister’s decision to save a few bucks and not send a STD or an invitation to her wedding that upset me especially, considering all the money I would spend in attending. Although, I decided to just let it go and never said a word about it to anyone.
However, I did decide to speak up when my sister took over plans for her bachelorette party and insisted on having a weekend getaway trip to Nashville, TN. Not only, did she completely refuse to consider any other alternative options, but she also insisted that tradition dictates the bride is not expected to pay for any part of the bachelorette party expenses.
Regardless, how these things are typically done, it just didn’t feel right to ask everyone to pay even more per person in order to cover all of my sister trip expenses. Her argument was, “I am the one paying for the wedding, I shouldn’t be expected to have to pay for everything.”
Our first disagreement, ended with her in tears, followed by a disrespectful message from her fiancé telling me I am horrible, unsupportive sister, anyone else should’ve been MOH and I should get a second job At McDonald’s if I couldn’t afford it. Afterwards, I felt like such a horrible person that I decided to find a way to do what she wanted in order to keep peace within the family.
It was yesterday, when I made the mistake of again asking my sister to consider an option different than her own, which I should’ve just kept to myself. It all started with my purchase of jewelry and hair piece since the April 6th wedding date was fast approaching.
When it arrived, I couldn’t wait to share with my sister the amazing deal I got on the set of jewelry I loved and matched perfectly. Her only response was, “you don’t need to worry about getting any jewelry.”
Apparently, she had already gotten BM personalized silver jewelry to wear (to match her)for the wedding and never told us as gift was supposed to be a surprise. Still, I had hoped she might reconsider given the circumstances that I couldn’t return sale items purchased and the gold would match the gold shoes and blush dress (her wedding colors).
Her response, “it was her wedding and only her vision of the perfect day mattered” and “if I didn’t change my attitude and wear the jewelry she had picked out, my invitation would change from MOH to guest.”
I am still shocked by her choice words. It breaks my heart to think that her vision of the perfect wedding included jewelry that was much more important to her then, her own sister.
At this point, I have absolutely no desire at all to even be part of this wedding and willing just to cut my losses on everything and the money I’ve spend on her wedding. My only concern is how this fact might upset my young girls and the example it would be setting for them.
If you’ve made it this far, thank you for listening and letting me vent, any advice is appreciated.