How (and whether) should I approach my psychiatrist about an antidepressant?

22M (diagnosed with bipolar disorder and a generic cluster B personality disorder)

At the moment, my treatment consists of Depakote 1 g per day and Abilify 400 mg once a month. I experience widespread lethargy during the day and a depressed mood. Until recently, my psychiatrist has dismissed my complaints, describing my treatment as "relatively mild" (although, to be fair, he has finally reduced Abilify from 400 to 300).

I would really like to start an antidepressant, especially Wellbutrin. Do you have any advice on how I should approach this? Or should I just point out the side effects I’m experiencing (like I did in the last 2 months) and wait for him to suggest the right treatment?

Some important information: I have a history of substance abuse (and my psychiatrist is aware of it), and I cannot/do not want to change psychiatrist.

Thank you very much in advance for your replies.