Accept my ultimatum, or I'll die.

Complicated question.

I am taken. He is married.
I am happy with my current.
He came in and made me fell in love.
Drama, loads of going back and forth.
Told the truth about us, boyfriend was upset.
I chose to make amends with boyfriend. He is in despair.
He threatens to kill himself if I don't pick him.
He says he will divorce his wife for me, anything.

But I'm dead set on staying with my current boyfriend and winning his love and trust back.

What can I do about this?
(He is currently in the hospital after we called the cops to intervene his suicide)