My ex threatened suicide several times. I knew it was only a warped attempt to get my attention, and scream out for help. This was apparent in the fact she made close family members aware of her plans as well. But one time she fired a gun in the house and that got my attention big time. After getting rid of the guns, I was flooded with the shoulda, coulda, wouldas AFTER the fact. I should have called 911 and she would have been detained and evaluated. It's hard to think clearly when you're chained to a front row seat of all the drama and mayhem. Getting opinions here is a great idea to help you evaluate different options you might have.
I called the hospital mental health information line and got advice and emergency phone numbers for during and out of normal hours. The lesson I learned was to never take these threats lightly and be ready w/ phone numbers to call if it ever happened again. And if it did, I WOULD MAKE the call and not flounder over the mind spin you go through as the SO of a mentally unstable person, (like I did during the gun incident).