This is also good advice, when my husband was suicidal for 18 months after first being incarcerated, I asked him to promise me that if he felt suicidal, he wouldn't kill himself until he'd been able to talk to me that day - since we spoke on the phone every day, and he most often felt suicidal at night, the promise to "wait until we speak again" would usually be enough to get him through the worst hours and by the time we spoke again he would be feeling better and no longer want to die, and repeat for days and days and weeks and months and eventually he no longer wanted to die.