I feel like one of the biggest hurdles for people suffering from BPD is being genuinely interested in their SO's life. They have a tendency to only take interest in their SO's interest in them. That is what they get from the relationship.

From what you describe, it seems you have surmounted that block. Unfortunately you seem to be left with someone who you do not find interesting.

Talk to him about this. I cannot express enough how much communication matters. The longer this goes on the more you will resent him and the bigger the heartache for him when it all comes crashing down.

Good luck with everything.