Juries are said to be hard to predict, but fortunately in this case there seem to be no disputed facts except the attempted strangling, which the jury will see straight through as prosecutorial over reach.The law says that he needs to either have intended to kill her (which he clearly didn't), or in the commission of an unlawful act that is likely to endanger a human life.
Not being a lawyer, I'm not going to speculate on whether the action of locking her on the balcony amounted to wrongful detention. But regardless, I think it's extremely difficult to argue that the act of locking her on the balcony was an act of intimidation sufficient to "likely to endanger a human life". And I think a jury will likely think the same.
I predict 5 years out in 2.
I would give him home detention with drug monitoring and one strike he's out.