Welcome!
As mentioned above, only get another bird for you...because your bird may not like the companion you choose for her, and they could fight. The other issue is that they could like each other too much and then you could have complications to your relationship, as well as potential hormonal factors that could impact health/aggression etc (even if they can't procreate, they can still get"weird" and that can lead to issues).
Either way, they may have to have separate interaction time for each (depending on the dynamics), so make sure you have to time to do that.
Whatever you decide, it's really crucial that you quarantine the new bird for 45 days in room far from your other bird and wash hands/arms/ even consider changing clothes between handling etc. They can be carriers of very serious illness without ever showing any symptoms. Your current bird could make the new bird sick and vice-versa.
That's why it's so important that you only do this if you are fully on-board and have the time for another bird, because it could complicate your life. I am not saying it can't be done, but just trying to provide some food for thought.
How old is your current bird?
