Reality check

All the movie is there to justify the final beat up of the evil ex-husband.

It's ok. It's a movie.

In reality, forensics will discover in no times the nature of his wounds.

In reality, if you wear rings (even with bandages) to punch a face, you'll just break your finger bones.

In reality, you don't developp the skill to beat the crap out of a stronger, heavier, taller, meanier person with your bare end in a few weeks.

If you want to murder your crazy stalker, there are more simple and safer solutions. For example, you could just:

1. Record him threatening to kill you.
2. Give copies to the police, to your attorney, put it on the internet.
3. Let him find you. Wait for him.
4. Let him break you door.
5. Blown is brain out with a firearme (preferably a shotgun)for home invasion.

Sure, it's less sexy than a great knuckle fight...

Or maybe, instead of great ninja technique, you could use this.

http://www.nononsenseselfdefense.com/stalkingsolutions.htm

At least, it has good chances of having real results without bloodshed.