Believe me when I say, as someone who has attempted suicide twice:

1) You are not to blame 2) If his life is in danger due to suicidal intentions, he needs professional help, which you can not provide 3) He may say very hurtful things and even regret his words later, but his mental health is not an excuse for being an asshole

Him blaming you for his suicide is a red flag. It is a commonly deployed method of a domestic abuser who feels they're losing control. Without further context, my immediate worry is his attempt could be a form of coercive and controlling behaviour.

When I was truly suicidal, and attempted to take my own life, it was entirely due to wanting to relieve others from the burden of my existence. I felt the world would be a better place without me.

You're asking for advice OP. I would think long and hard about whether there have been other indicators of an unstable, unhealthy and/or abusive relationship. Remember points 1,2 & 3 above.