I have four dogs in our household (with three people), and amongst the three, I am by far the strictest disciplinarian. However, all four dogs prefer my attention and affection. In fact, it's quite similar to what you describe in your household... when I'm not around, the dogs do fine with the others in the house. As soon as I enter the picture, they pretty much ignore the others in large stretches of time and only respond to me.
If you never reward the dog, then yes, take some of the advice above and reward your dog, but only for obvious things and not overdo it. Otherwise the dog will see you as nothing more than a treat dispensing machine, and you don't want that.
Also, by now, it's pretty obvious that your dog has bonded with your partner. She still loves you, but as a result, you will probably never elevate to the same status as your partner. However, below are some things that I recommend to at least elevate yourself in her eyes:
(None of what's below is to indicate that I know how you treat or behave with your dog, as I don't know. So I am not being judgmental or critiquing what I don't know about. This is merely how I treat my dogs vs what is lacking from the others in my own household by others)
1) Be playful with your puppy. Actually take some time and have one on one time, with or without your partner around. Use toys some times. Don't use them at other times. Use a toy or rope to play tug of war, and let your dog win after an appropriate amount of time (and obviously before the puppy gives up).
2) Show respect to the dog. Give her her own space, allow her to be by herself. Don't insist on her being next to you at all times.
3) If you have to discipline her, use an authoritative voice and not a mean spirited one. Never yell at her unless it is absolutely necessary (usually when you are trying to avert a dangerous situation). If you ever do have to yell at her (again, a VERY rare instance), immediately tone it down to a non-yelling authoritative voice.
4) Be respectful and fair, even when disciplining, and don't discipline when a simple redirect is really all that's warranted. For instance, don't yell at or discipline your dog just because it sticks it nose up toward the counter when it smells a new food item or treat bag you just opened. This is a moment when a simple (and gentle) redirect will suffice and perhaps a simple "No" will do.
5) Never hit your dog, even when disciplining her. Don't discipline if the dog goes to the bathroom in the house.
6) When she enters the room with you in it, or you enter a room with her already enter it, show genuine enthusiasm that you are happy that you two are together. Talk to the dog in a "happy voice". Give it a pet or rub where she likes it (neck, head, belly, etc...) Don't try to fake it. Many humans can pick up on fake enthusiasm, and dogs are even better at reading our emotions.
Hope this helps.