Is it advisable for someone with BPD to be in a poly relationship?

I have been diagnosed with BPD and am poly. How good or bad a fit for you it would be will depend on a ton of factors. How aware and insightful about your emotions and recognizing them are you? How are you doing with your communication and self-talk? Can you continue to feel secure about other types of relationships when they have others in their life too. Are you in treatment? If yes, your therapist or med manager might be the best resource for your specific case as they are more familiar with you in particular than strangers on the internet will ever be. If you think you can handle it, and you really like this guy, I suggest doing a ton of research, maybe join some Facebook groups, reach out to your local kink community if one exists in your area (fetlife can be good for finding this out) as there tends to be a lot of overlap between the communities and you could build friendships with folks who are more likely to be supportive of your relationship structure than the average Joe on the streets.