I think i may have confused you. My sentence
about brandishing a weapon went to your comment about your 20 year old matter -- in some states just holding the knife (even to put it out on a table) while making a threat would make out brandishing or menacing charges. So, yes, sometimes just being in someone else's face is enough to get you charged with a crime if the complainant wants to report it as such. I was not discussing what happened in the more recent incident you would like to have prosecuted.
As to that incident, if the state is willing to file charges, then the two will be arrested or given a citation/summons and become criminal defendants. From there, no matter what happened with the case, the fact that the case was charged will turn up on their records.
If there has been ongoing strife since this incident to the effect that you have real worries that another such incident will occur, you can ask the prosecutor for a protective order to make them keep away while the case is being fought (and, if there's a plea or conviction) for a period of time afterwards.
I've made my mistakes too when it comes to love, but I don't think that we women have a lock on wanting to fool ourselves or on hanging on too long to the wrong person. Love is blind and an equal opportunity employer -- can make fools of all of us at one time or another, regardless of race, gender, color or creed.