Cats are very independant. Some cats LOVE and crave attention from humans, while others just want to be left alone and will come to you for attention when they want it.
The kitten does sound to be jealous, and bringing in another cat as a remedy to her not being cuddly enough with your fiance was probably not the best idea. Bringing in another cat will definitely not make her want more attention or make her want to be cuddly.
Here are a few pieces of advice/ info I can offer.
1. Give it time for the kitten and the new cat to get used to each other. It can take weeks for them to even tolerate each other. They wont get along right away, but I would guess that if given time they will become friendly with each other. I am guessing that the kitten probably is scared or intimidated by this older cat in addition to being jealous and she is probably on edge.
2. The more you try and force a cat to sit with you, cuddle with you, and give you attention, the less they will want to. I guarantee it. I would suggest that your fiance ignore the cat and wait for it to come to her. Cats dont like to be forced to do anything and the more you try the further you are driving it away. I read somewhere a while back that cats seem to gravitate to people who dont really like cats and I have always noticed that with my kittens. I have a friend who doesnt like cats and they seem to gravitate towards her and come to her for love. The reason for this is because people who love cats seem to watch the cat more, stare at them, talk to them, try and get them to pay attention to them, etc., as where someone who doesnt like cats doesnt bother them and leaves them alone - so they dont feel as threatened by them.
3. Dont ever expect a cat to "respect" you. Cats expect to BE respected, not give respect lol it's just how they are. If you want unconditional love and respect, a dog would be a better choice.
4. usually after getting a cat fixed they seem to calm down and be more mellow. Also, with age, she will possibly get more cuddly. I have a 3 year old cat that was never cuddly even as a kitten, and now she is much more cuddly. But, she comes to us when she wants attention, and if we try and force her she fights it and gets mad. The older she gets the more she comes to us for attention and love. Some cats though will just never be the cuddly type.
Cats (or any other animal) are not things you can just toss aside when they dont act exactly how you want them to, and it's really not fair to the cat that you would bring her home, let her get attached to you and comfortable in her home and then just return her or give her away. If you had adopted a child, would you return them if they didnt have the exact personality you wanted them to have? I know that sounds like a drastic comparison, but it really isnt fair to the animal. If you end up deciding to find her a new home, I hope you will make sure it is with a loving person who will give her a lifelong home, and do it soon before she gets even more attached to you and your home.
lastly, please dont think that a male cat will be different just because it's a male. I have four cats and the one that is the LEAST cuddly is the male. he also occasionally likes to show his dominance by picking on my girl cat. Also keep in mind that male cats will sometimes spray to mark their territory, so if you get one, make sure to get him nuetered as soon as possible. Most of the time if you neuter the male cat before it reaches its sexual maturity, this will keep them from picking up the habit. A lot of times male cats tend to be more cuddly, but not always. You just never know what you are going to get. If getting another kitten, get one that has been regularly handled and seems to like to be held, etc. from the beginning. That wont guarantee it will love your fiance or love to be cuddled, but it helps if they were regularly handled as babies, opposed to a feral kitten who hasnt been handled a lot. If choosing between several kittens, sit down for a while and choose the one that comes to you, the one that lets you hold it without immediately wanting to get down, and one that seems comfortable being carried around and handled.
Good luck.