If your depression is situational, I think that the paxil will help you through the rough spot and then you will be able to go off of it.
If you have a chemical imbalance, then you will most likely have to continue using it.
Is your bf taking anything for the bp? I would encourage him to counseling and or medication if he isn't already doing so.
I too wonder if your boyfriends BP is being medicated? As Karen has already said, it depends on what is causing the depression as to how long you will be on it. If you are worried about becoming addicted and you need a long term med, then there are plenty of others out there. Talk to your doctor if you are worried, but if it is only short-term, i wouldnt worry too much.