Oliren, I know this is hard. I'm sorry.

I have been in a complicated relationship with my BPD and we currently are not together but might as well be.
Can you give us a little more detail about how the relationship is complicated? Details can be helpful, especially if you want to set boundaries. It sounds like he wants a relationship with you, but is saying 'not right now.' Is that accurate?
They are constantly making me feel like I am in a competition I won't win. I cannot handle being told I'm the "end goal" while he works and hangs out with a friend/coworker who I feel is attached at his hip.
Is this the girl that you mentioned before? His good friend?
Am I the one who has to make all the changes?
It's hard to be the person that feels the full weight of having to make changes to make it work. I used to do ballroom dancing. Advanced level dancers would get frustrated about dancing with newbies, and the instructor would remind them, "Who does the adjusting? The one that can." Advanced dancers had been doing it long enough, they knew a few ways to adjust their technique. Newcomers were still nervous and memorizing basic steps.
Most of us here are doing most of the work. At least, we get the work started. Two things to keep an eye on: (1) make sure you're not sacrificing all of what you want, because if you do, you'll just resent him. (2) Look for progress. When you see your work pay off, the resentment has a way of evaporating.
It would help to know what he is communicating to you about your relationship, and what you want going forward.