How should someone handle their partner's PTSD/panic attacks&bipolar mood swings&occasional self-harm setbacks? Esp in serious long-term relationships

Get support. A person's emotional problems can be just as stressful as physical illness in a relationship. Suggest you see a mental health professional for guidance and support. Be sure to make time for yourself. Connect with others for help. Look into NAMI or local support groups: . I hope this helps. Best wishes.