I don't think its selfish because when you get to the point of suicide, its either gone beyond the point where you are able to think about the effect it will have on others or thinking about it and what a horrible person it makes you just makes you feel worse and more suicidal. I have no first hand experience but have heard both things said by people whose genuine suicide attempts failed. The next day after telling us what a dreadful person she was and how awful she was because she had tried to commit suicide, she did it again and succeeded.
For me selfishness is knowing what effect your behaviour will have on someone you love and not caring, not being unable to care.