I'm getting my permit soon and have been doing a lot of reading on things like this as well as going through a lot of scenarios in my head. I'm a night janitor at a bank and most of my scenarios have been related to that but something like you've posted is very possible. I don't know if I would be quite so quick to draw unless the guy was armed. Then if he was, I'd have to quickly make the decision, before drawing, whether I'm willing to pull the trigger in that given situation. I think first, if you have other people with you, try to defuse the situation, get the female involved away from the a-hole and see if you can get things to cool down. Every situation is different with a million possible outcomes but constraint is usually going to be the most desirable action. BUT in your scenario, when you've had to make the decision to draw and the a-hole has complied, I would make him stay on the ground, face down, arms out straight until the cops arrive. Also I'd make sure that whoever calls 911 lets dispatch know that you're armed and what your description is so the cops know what to expect when they get there. And, maybe have your gun put away just before they actually arrive. Having friends sit on the guy can be a big help too. As far as zip-ties, just something else to carry around but yeah, could come in handy.
If the guy tries to run, do NOT shoot him! That will make life a living hell for you. Let him run, the cops will find him later. You've stopped possible spousal abuse which should be your primary goal. Most of the time, the victims end up not filing charges anyway, which is another topic altogether.
Just my 2 cents worth, probably worth 3/10 of a cent, what with inflation. :-)