Is this a relationship with your romantic partner, or with another relative such as a child? Can I ask what the "first steps" are in your case, like just laying down boundaries verbally of where the lines are that shall not be crossed, or are you past that and into the separate living arrangement timeline?
Like grief, we go through phases leading to acceptance of the reality of BPD - so I'm glad to hear you're coming to terms with the fact, yes, it is indeed always going to be one-sided and it is unlikely the other party will ever do as much to self-improve as you will (although there are happy exceptions!). Personally I spent the longest time stuck in quasi-denial, I accepted that it was BPD...I just refused to accept that it was terminal. I convinced myself that enough compassion, enough tough love, enough hours spent sitting them down to discuss the problems with their outbursts...surely a breakthrough was near! (It wasn't). It's humbling, when you finally admit that yup...I found a problem I could not solve.
