I’m not very active on this sub but I’ve lurked for years, in all that time I noticed many posts about partners of people with BPD reassuring that everything is fine, that they will never leave us, etc. then they suddenly leave. I’m talking leaving literally days after saying that. 

I might be biased because I have personally gone through that, but I really have seen so many posts where that happens. 

For me it happened years ago, but I just saw another post that mentioned it and that got me thinking about this occurrence