Borderline personality disorder often means that the person is emotionally unstable. If you're willing to live with someone who suffers from it, you need to be very mentally strong as it will no doubt be a very difficult task. Ask yourself if it's worth it and if you're able to get that person the help that they need.
If the person you’re going to live with is in treatment for Borderline Personality Disorder, that is already a big help. They should be actively taking steps to learn de-escalation skills and how to correct distorted thinking. The best way you can get along with your loved one with BPD is to ask them for information about their triggers and how to help them de-escalate. Be aware that both perception and cognition is distorted by the disease, so there may be vehement disagreements from time to time about what exactly happened or what was meant by someone or something.
I would say to do as much research as humanly possible on the topic. You should also know what your limits are and what you will be able to accept and tolerate. Lastly, you should ask yourself if the person you want to be with means enough to you, that you can live with that disorder on a daily basis.