The most important issue here is the attempt to die. There may be circumstances where death is preferable to life, but for the most part it indicates a severe emotional imbalance which is both life threatening and cause for immediate medical intervention.
When an otherwise healthy person has the desire to end their life without extreme circumstancial trauma it indicates a chemical imbalance in the brain, just as sugar in the urine indicates a pancreatic disorder and we all must re-learn how to react to this situation.
A husband, father, mother, girlfriend, child, ect.. is not equipped to deal with this situation any more than they are equipped to perform brain surgery. The victim of this condition requires medical attention, the sooner the better. If they are unwilling to be treated and nothing you do or say will convince them to get help, then it may be that they need to be committed for 72 hours of observation at a liscensed facility or emergency hospital.
If I sound harsh, it is bacause I lost my 26 year old son to suicide. We did not recognise the symptoms til he was gone and it became too late to obtain help for him.
My advice is this: Stop at nothing to save a life.