I'm having the same problem. I can't approach the subject to my mom without her crying and hinting suicide too. I believe everyone else would move on, but my mom wouldn't.
The best "tip" I can give you is to try and explain the dimension of your suffering. If they know how much you were suffering, they might start seeing your death as a good thing for you. Make no mistake though, suicide will always be considered a tragedy to most people no matter what. And I kind of understand, because it's a death that *could* be prevented, 85% of suicidal people usually drop hints or act different prior to taking their own lives. It's also awful to find out someone you loved was going through so much pain, but I believe if you can make an analogy comparing mental illness (if you have any) to physical illnesses, and how they shouldn't be viewed so differently, that might make it *less* horrible.
Any advice on how to convince loved ones that my death is a good thing? I've tried using the "if an animal is wounded bad enough, you put it out of it's misery" analogy but it doesn't seem to really work. Personally I think it's selfish of them to want me to stick around if I'm hurting for years and it won't stop. I don't want to be here. But they want me here. So here I am.
Also, I forgot. It's unlikely they will just say yes, you can CTB no problem. I've been trying to convince my mom of my death for 5 years.
The best case scenario would be writing a letter and explaining things.