The "outcome" will be prison time, that is a guarantee especially with his history.

But, her credibility will affect the length of his term in a big way. If she lied about them being involved (and it looks like she did as her police report did say "boyfriend" and other reports said they broke up), then he can play the emotional outrage card at seeing her in bed with a guy. That will affect time offered in a guilty plea deal, or in a trial.

At the end of the day, he could get anything from 1 year to 10. A lot depends on whether they can prove they were still a couple or not as that can play a factor. If he can NOT prove they were still involved, then randomly showing up at their house and beating the fuck out of both of them is a very serious thing and he will have the book thrown at him. If he can prove they were together, then he can play the emotional outrage card and will get a lesser sentence.

But whatever happens, he is going to be doing time.

And when he gets out, there will be tons of women contacting him to hook up. THey will all think they can bring out the good in him and harness his anger and vitality and all that crap and think that he will never harm them.