
Welcome! You've found a peer support site where we have an immense storehouse of collective wisdom, won through experience and education. Others will chime in soon with their thoughts.
Briefly... You can't fix him. If he wants to find a measure of recovery from his issues, likely he would have to seek a professional to guide and advise him, for years and not just a few sessions. And that's not you. You have a history with him, a close emotional relationship and that aspect is too much emotional baggage for him to really listen to you.
Also, suicide threats ought to be addressed by those trained to handle and assess them, whether emergency responders or hospital services. You as an ordinary spouse are not considered trained to determine whether they are actual suicidal ideations or manipulation attempts.
Let the trained personnel determine that. However, we can almost guarantee that when you make the call, your problem person will Deny any such behavior. So... did you have it recorded or have a witness that can vouch for your call?
On the flip side, call the experts and you may find there are fewer suicidal threats in the future. Ponder that.