My wife is my PA, how do I reprimand her? Or do I just fire her now?

I work in an industry with much admin and I have been testing a setup where my wife works for me half day for a few weeks now. She has a small one man business that takes up the rest of her time. We have no kids or other commitments. The mission is to save the money I would otherwise have to spend on a PA by keeping the cash in my household.

Some days it works out brilliantly, she is actually very good at the work I give her, she makes me coffee and takes direction like a sexy little mistress.

Other days she comes to work late and when I reprimand her for it, she gives me a shitty attitude of "who the fuck do you think you are telling ME what to do". You should see the look she gives me, I have sent her home before as a result and threatened to "fire" her. This happens mostly when we argue at home before work and it spills over to the office - this is drunk captain crap I know, I am busy handling it.

At work I command that it is strictly an employee/employer relationship and that she has to follow my lead like a normal employee would. This is the only way husband and wife can work together I feel.

When she gives me shitty attitude currently, I simply feel disappointed in her and no need to give her any attention, then go focus on my MAP instead. But at work I actually need to talk to her and be happy about it. This attitude is so vile that I even feel the need to next my wife entirely. Her business is actually just a hobby of hers that sometimes makes a little money, no where near enough to pay even half of her life's costs.

So my question is, how do I reprimand her at work as an employee would have been? Or do I fire her and pay the extra cost of an employee. My real employees risk losing their income or getting a written warning which could lead to being fired; my wife knows if I "fire" her she will just sit at home and relax while I have to pay the bills. I don't feel this is shit testing, I feel more like it is simply her being so lazy that she does not feel the need to work or contribute. I feel I am not OYS entirely here.