Hi KeepCalm,
Can anyone share stories about how their SO with BPD has broken up and how they made up, without repeating the toxic cycle?
the challenge is repeating the cycle not the making up. The latter has little to do with the former. It is tempting to think that you establish rules first and those help you to prevent trouble later. But the trouble stems from immediate and emotional not rational challenges so negotiated agreements are meaningless.
Typically there are 3 paths:
1) Stay broken up.
2) PwBPD starts working on themselves through therapy (or other experiences) and changes to a degree.
3) Change yourself. Make up and you change the rules you let yourself treated (see all the workshops on Boundaries). This may well lead to another, possible multiple and possible final breakups. Over time the pwBPD changes as the broken behavior proves not effective anymore and some less broken and some healthier behavior is learned through experience.
I don't think conflict cycles are totally avoidable in most cases. In some way they are part of being human. You will find 2+3 on the improving board and progress is often there in severity and frequency of "toxic cycle".
All paths are more or less painful . 1 provides clarity. 2,3 are not under your control alone.
For a long term success some degree of change on both sides will be needed. But then change is hard to initiate across the board. Change often starts with commitment in a corner and takes over the board.