Sorry for formatting on mobile 

So recently with Valentines day my girlfriend decided to get me a preserved rose (for those who don't know this is a rose that doesn't die and doesn't need watered). While I was out this morning my mum decided to spray the rose with some water, despite having been told that it's preserved and doesn't need water.

I come home with my girlfriend to find my rose sitting there looking like it's wilting. I am hugely upset by this and I want her to pay for the rose as its quite pricey.

This is where some context comes in.

About two months ago both her and my grandmother went halves on a new car for me and I am paying her back $200 with every paycheck I get (which is about a 5th of my paycheck, with the rest going into bills and savings).
Today happened to be one of her pay days (from me as she is unemployed and not actively looking for work) and I took out the cost of the rose from what I owe her for the fortnight. She immediately got angry and demanded the rest of the money. Its emotionally affected both me and my partner and is continuing to do so. 