Girlfriend threatening to commit suicide.

Good morning...I'm a 36 year old married man...but I have problems in my marriage and doesn't have any physical relation with her for a long time...we mostly Live like roommates...in March I have received a message from a girl on Facebook...and we started chatted there...she was in an abusive relationship with an alcoholic husband...we talked and started liking each other and have made physical connection with mutual consent. Now in just couple of months she has become extremely abusive and fight on the very small things and threaten me with various things like she will call police or do something to herself. One day I was not well and did not message her all day...she abused me so much and threatened to call police. In WhatsApp message she even agreed that I never do wrong and she is an abusive person and needs to take her frustration out. Now yesterday we disagreed on something and she told me to not message her or call her otherwise she will call police...I did not contacted her but later she messeaged and abused mw and threathen to commit suicide. and later file any case against me. kindly guide. i did promise her to marry and i wanted to, but her abusive side really scaring me and i cant marry her.