My girlfriend [22F] keeps threatening to kill herself whenever we have an argument

My girlfriend [22F] and I [23M] have been together for 5 years now. When we first met she was the most loving, caring and understanding person Ive ever met. I could tell she had issues (which she admitted to) but I loved her for who she was. Shes beautiful, smart, funny and has the biggest heart so it was easy to over look her flaws and support her through her bad days.<br><br>The problem is, whenever we have any type of argument (big or small) she always threatens to kill herself. Whether it be saying she wants to die, claims shes currently self harming, or telling me she found pills and is thinking about taking them (she has a history of Pill abuse/Suicide attempts) it always stresses the hell out of me. She knows how much I value and care for her life so she uses that against me. Shes used this on me so much that Ive started avoiding confrontations with her. Ive started letting her win arguments so she doesnt go through with it. <br><br>Shes also gotten violent with me. When we were on holiday, i made an angry comment in the heat of the moment. She told me she found a bunch of pills and was gonna take them because of what i said. I was in shock and had no idea what to say to her or how to make it better. She ended up punching and scratching me till i apologised and told her the comment didnt mean anything.<br><br>Ive stood by her through thick and thin. I do everything in my power to make sure she is safe, happy and comfortable. However the last few times she pulled this, Ive found myself less affected and more angry at her. I dont feel like someone who threatens to kill themselves all the time whenever they dont get what they want should be in a relationship.<br><br>We have an upcoming trip to Japan together and I honestly do not know how to approach her about this or if I even should. I know shes going to be upset, but I dont know how much more I can deal with this. This trip was for her birthday and shes really excited but I honestly dont want to go if this is going to be a regular thing with us. Whats the best way to approach her about this? Do I end things with her before or after the trip? Shes going to feel betrayed if I end things with her. I feel like I've failed her as a partner. This trip was also supposed to be where I proposed to her.