<human>: Can you condense the text into three sentences or less?

My Gf and I have been together for 4 years. The majority of the time she's amazing. But ever since I can remember she's had a short fuse. It is often triggered by minor occurrences like her phone freezing and the refrigerator door not closing. These often lead to tantrums and her yelling at me. When the refrigerator wouldn't close, instead of looking inside to see what was blocking it, she repeatedly slammed it open and close and got angry at me for it not working. When anything goes wrong it's usually followed by slamming and her yelling "WTF JOHN!"

I've become extremely cautious of what I say around her because saying the certain things set her off instantly. I also try to keep the house arranged and organized to try to avoid triggering her tantrums. 

2 nights ago she went to the gym. Last night her leg was sore and she wanted me to feel it because it was hard. I felt it then felt mine to compare because I was unsure if it was normal. Immediately as I felt my leg she got upset saying "FUCK! Nevermind! Sorry I'm not skinny like the girl on TV or like your ex!". It caught me completely off guard as I had not said anything. I have never said I wanted her skinnier and nor do I ever talk about my ex's.

It's hard for me to be around her when she throws her tantrums or when it seems like she's a time bomb. How can I prevent setting her off?
<bot>: Gf gets extremely angry at minor things and often takes it out on me. How can I stop her from throwing tantrums?