The biggest problem I see is your relationship. The fighting and the dependency... Also seems like there's a lack of trust and respect. Is this a long-term committed relationship? If so, I think you should tell him about the BPD. If it's not, then don't tell him. But from what you wrote, your relationship sounds unhealthy. I know you're dependent on him, but maybe you should make sure whether or not this relationship is what you need.