Welcome

commonope,
Sorry to hear that things have been so hectic in your relationship. I'd like to second what
RolandofEld said about not buying alcohol for him. I do the same with my H and cigarettes.
When your partner makes accusation against you, how do you usually respond? I now for myself my first response was to start trying to explain or justify myself which just made things worse.
One thing you might try is to just try to dig in to what he means by asking him questions: "What part of what I said was mean?" "I'm confused. I want to understand what you are feeling. What body language did I do that was rude?"
This prevents you from having to take the blame for it and it puts the attention more on what he is experiencing than debating what really happened. To someone with BPD their perception=reality and to disagree with their perception=rejection of them. Responding in a way that allows them to just talk about their perception can often be enough to let them know you are listening and often they want to know you care more than being right, even though it seems like they need to be right. Does that make sense?