A consenting adult is the arbiter of pain in his own life. We let them inhale carcinogens. We let them decide on who should direct their destiny in an election. We allow them to go off to war and perhaps lose their lives. Are you saying they can't hold their lives in their own hands -- that The State should control our lives?
@Suppressed Just so that you are absolutely clear you have just said that it is perfectly acceptable for someone that is distraught over the actions of their spouse is justified in ending their own life.
Let's take it up another notch at what point does it change from optional and voluntary to mandatory? Denmark and Iceland are aborting Children with Down's syndrome at an unprecedented rate. What about when Grandma develops Alzheimer's disease and it is too costly to put her in a home?
When you decide that man has the power of God to decide their own time of death you better make sure that you are ready for someone to decide to play God with the time and place of your death, because that is the very next step.