personally: some years ago, i was very open--2 the point of being a fucking asshole--about me eventually ctb 2 my ex-gf. she tried 2 tolerate it as best as she could, but she didn't see things from my end, n i couldn't see things from hers @ the time. my arguments @ the time were that some people have a shittier quality of life than others as it goes on n that it's a personal choice n my right 2 end it as i saw fit, her argument was that this line of reasoning made little sense 2 her n she didn't want me gone. although she never said it 2 me outright, i'm certain she thought me very selfish 4 doing it, n i think she was hurt significantly by the fact that i wanted 2 die more than i wanted 2 stick around and be with her. this was years ago; i still wish i'd never said anything. if people care deeply about u, they're likely to be hurt by it, as they inevitably take ur decision 2 ctb personally--they don't want u 2 leave em, n i can imagine it's real hurtful 2 have some1 u love choose death over u.
objectively: i got into a drunk debate w a friend regarding suicide, my pros: some people suffer in a way that the only was forward 4 em is out, it's a personal choice, n if it's well thought-out n not hasty it can be a pleasant means 2 an inevitable end. she started crying, told me 1 of her friends was suicidal (not referring 2 me) n if that friend ever went thru with it she'd be pissed n upset beyond belief--it'd be such a selfish thing 2 do, n a horrible waste of potential, n how are things supposed 2 get better if u don't give em the chance? i didn't want 2 upset her further so i dropped it.
TLDR; same, op. personally n objectively, nobody i've spoken 2 sees it from my side of things n the people i've talked 2 think it's a selfish thing 2 do