Coincidentally, I just saw an interview with Kevin Hines. He survived a suicide attempt - he jumped off the Golden Gate Bridge.
He said in the seconds after he jumped he deeply regretted it - but what he felt just before jumping was what he called 'Lethal emotional pain'. A pain so great it leads you to believe you're worthless & a burden to all who care about you. Of course it's not true - but that's what was going through his mind when he decided to end his life.
I used to think 'how selfish' too - especially when children are involved. Apparently nothing else crosses your mind but stopping the endless internal battle you face every day.