My death also would be traumatic for my family, but they don't deserve me, so my own well-being is a priority. Being selfish is considered as something bad, but we all need to be selfish sometimes.
That said, maybe your case is not the same as mine. Do you have a healthy relationship with your family? Have you talked to them about your problems? If recovery is possible, maybe you could try to talk about it with them. If recovery is not possible, maybe you can try to make them understand that you need to CTB. I feel like if you disappear suddenly, for not apparent reason, it would be worse for them.
If not, I'm not sure myself how to deal with it. I'm lucky (?) that I don't have no one who I care about, so I don't have this problem.