IMO and IME, if you have BPD, the chances are high that your FOO are like an emotional viper pit. You will never be able to try out normal, healthy operating with them, they will just reinforce your symptoms over and over. So don't beat yourself up here; you're literally trying to get better while dealing with the people who likely made you develop BPD in the first place.

This is especially the case when it comes to learning how to communicate calmly but assertively, because people with BPD usually have at least one person in their family with a history of going after emotional vulnerability like sharks smelling blood in the water. So you can get into this situation where you're supposed to work on communicating your emotional needs, yet you know that if you expose any 'weaknesses' then someone is going to take advantage and try to get at you with it.

You just can't get better when you're trying to use dysfunctional-*** people to practice with, be they friend, family, or whatever.