I’m going to start by saying you need to have a frank discussion with your fiance about who’s responsible for the cat. I’m taking a bit of a leap here, but it sounds like this isn’t the only problem with communication between you two. Also, and I think you know this, but taking the cat to a shelter will put a wedge between you and your fiance if she isn’t fully on board with the idea.
As for the cat, well, she’s a kitten. It’s what they do. But it won’t be forever, she will start to calm down in about another 6 months to a year. The constant need to play will start to disappear and probably turn into the need for lap time. She’s a lot of work now, but when she’s fully grown she’ll be a lot more independent and easier to handle. You might even find she’ll become a great companion once the kitten energy wears off.
As she grows and learns how to cat, her instincts are telling her what to do when she encounters prey. And the only way for her to get good is to “practice,” unfortunately on you. When she starts, grab one of her toys and dangle it in front of her. If she starts going for it, toss it for her to chase.
A toy I suggest you get for her is a Kong Kickeroo. She’ll be able to wrap herself around it (like I assume she tries to do with your hands, arms, legs and feet) and really go to town on it. It’s good for her and good for you, since she can burn off her energy without causing you pain. To add to her enjoyment, you can grab the tail of the toy and give it gentle tugs while she’s wrapped around it to mimic the toy “struggling” to get free.
I hope some of this will help!
Look into under desk cable management. You can get trays that screw into the bottom of your desk to run the cables neatly and most importantly off the floor where a kitty can get them.