How are people who commit suicide selfish when it's their life?

People say those who commit suicide are selfish but I disagree. People usually commit suicide because of the mental/physical/emotional pain that they feel they can no longer endure. So how is killing themselves selfish when its their life ? And when they're the ones who have to endure the anguish all alone? People say because their family will miss them but isn't that selfish for their family to want them to continue in the pain they were in just so they wouldnt miss them? Thats seems selfish to me.