Ah. My budgies are pretty independent, and more bonded to each other than to me. However they were used to having ALL my attention until I brought Sunny home, and as mentioned there were definite jealousy issues for a while.
In your case, as with anyone bringing a second bird into their life, you will need to continue to make Lots of time available to maintain your bond with your first bird, while at the same time, equally lots of time to bond with and train your second bird.
Maybe people have birds of different species. Definitely that can work. Quarantine the new bird to start with. Be aware and cautious at all times, make sure you are watching over their interactions, make sure you have time for interacting with them individually -- and, hopefully together.
As mentioned elsewhere, when you get a second bird, they might hate each other, they might love each other as best-buddies, or anywhere in between. That said, budgies tend to be very friendly and curious. Chances are good that, once over any jealousy, your budgie will probably like your new bird a lot. OFTEN with budgies, the biggest problem is they can be annoyingly sociable. Quite easy for sociable bratty budgie to provoke a larger bird resulting in harm; this will be something to guard for in their interactions.
The biggest qualifier for getting a Second Bird, is that YOU want it. (That is, don't get a second bird FOR your first bird, only get a second bird for YOU.) You definitely meet that qualifier.
SO if you have time, space, and love & attention to give 2 birds, then definitely do so, and get the second bird that You want.
