I don't understand why the word sorry is written at the front, it certainly doesn't fit there.
It mightn't be the best idea to be living with a partner at this stage but that doesn't mean it's immature. Considering they have BPD, I don't find it surprising or unusual. I'm not respectfully disagreeing with you, because you didn't make your comment respectfully.

Relationship issues are a huge part of having BPD, if you can't understand or accept that then maybe you shouldn't comment on the posts about it.