If it were me, I'd just stick with one dog... unless there is a particular dog that you already have in mind that really needs a home like yours...
Like others have pointed out, Pami is used to being your one and only and getting loads of training and attention. My first dog was like that too and I never would have gotten another except I had opportunities to participate in various dog activities that Max couldn't do (due to temperament and joint issues), so I decided to get Charlie was able to do those activities and I focused on other activities with Max.
Max loved playing with the new dog, but our relationship changed... Charlie was so pushy and off-the-wall that I had to 'deal with him' while Max was so good and easy he just faded into the background unless I put Charlie in a crate to give Ma special attention
Charlie is a very different type of dog and after Max passed away and he was an only dog for most of a year. He was never cuddly and didn't seek-out any attention from me... he prefers to be on his own, doing his own thing. So for him, it was really easy to add Harmony - now he seems to be saying 'About time you stopped trying to hug me - go get your puppy!'. And Harmony loves getting the attention.
If you do get another dog, I think you'd have a better chance of Pami not feeling so 'replaced' if the other dog is an adult. If they are a puppy you will need to keep them right with you to prevent accidents, which may make both dogs feel like the puppy is the special one...
Lots of things to think about ...