If money isn't an issue, I suggest at least getting one
Prodigy V3.1 kit from puresmoker.com. I recommend 3.7V setup. It's all mechanical and can run any type of atomizer/cartomizer you like. At least take a look. Once you try a mod to see how much vapor, flavor, TH production is increased, you'll see why I recommend this model. One battery lasts me a full day of vaping and I'm a heavy hitter...6-7ml a day.
Or, look around for a cheaply priced 3.7v box mod if you don't want to spend that much on the Prodigy. Get the recommended batteries and charger for it.
Next, I recommend either Boge low resistance cartomizers or dual coil cartomizers. Both are very easy to fill. Remove mouthpiece, hold at a 45 degree angle, and drip down the side avoiding the center airhole. Let sit on threaded end for 20 minutes and top off with juice if it doesn't look slushy on top of the filler material. Duals can be filled the same way. Another way is to use a syringe and poke it gently into the filler material and squirt slowly. Move the needle around so that all the material gets saturated.
No matter what you buy, as long as it works for you and your wife, you won the first battle. Just make sure that everything you buy, fits your devices battery threading.