Its the nagging thought that i could have perhaps behaved differently and we would have been able to make it work thats getting to me,
Right, toughday, that's what everyone thinks, which is why so many Nons (including me) end up recycling, often many times, only to end up in the same place down the line, except with more pain.
I'm sure you do have fond memories from the roller coaster ride and fireworks to look back on, but it's best left in the rear-view mirror. In my view, it's a lot better to find someone kind, with whom you don't need to walk on eggshells. I'm happy to be off the BPD bus.
This might be a good time to ask yourself why you got involved with a person suffering from BPD in the first place. Hint: Usually it has something to do with one's FOO or other childhood trauma.
Keep posting and I'm sure you'll hear from other folks around here.
LuckyJim