Practice, practice, practice!! That is the best way to become proficient with your self defense weapon. It is sort of like driving a standard transmission vehicle, you remember how, but the mechanics of smoothly changing gears will escape you after a while. Loosing the mechanics of smoothly firing your weapon is not a good thing.
Practice with solid or ball ammo as this is most economically feasible. Hornady makes a good self defense load called Critical Defense that I would recommend for this gun. I have found it at www.cabelas.com
. I have had to wait a couple of weeks, but I have gotten it as well as practice ammo from this source.
As for your need for the weapon, I am sorry to hear that. A relationship gone sour is a bummer in any event, and one that has gotten really ugly is a shame. Go forward and be safe.