Dear Ark,
I guess you've posted in the right place for sure.

It's so hard when you feel you're walking in eggshells with someone you love, and I totally feel you.
and he switched and said he didn't want to stay at mine, a few days ago he was talking about how excited he was for these plans bearing in mind. I asked him why and he replied saying he isn't feeling this relationship anymore.
This just reminded me of how my partner changes/had changed before from the morning telling me how much he loves me, to night telling me I make him bored and he has always hated me!
I'm also new to this, even with knowing that my partner has BPD for +3 years. But recently I've been thinking that people with BPD are more like children than adults, specially in emotions, even though they may actually seem and act so mature when they're not triggered. They don't really understand when their partner has some comments on a part of the relationship not them, and this won't lead to a break up. Just like a child when they get shouted at from their mother, and they might think their whole existence is wrong and their mother is going to leave them (and this was actually a big fear in my partner's childhood). This kind of thinking helps me get less confused and shocked when I see such reactions from my partner, and I tolerate the space between us better.
I haven't spoken to him since that last message. I know we always sort things out but in the back of my mind I always have the doubt of what if we don't.
I hate it not speaking to him I just want to text him and tell him I love him and to stop being silly but I know he can't help it.
Personally I never thought there would be someone out there that feels like how I feel. I completely feel you. Maybe we expect somewhere in the corner of our minds that maybe we just tell them "I love you please don't be silly finish this space between us" and they just come back, but we also know that's not how they think and behave.
I don't know how you can help him with splitting episodes, that's also a question of mine. What I always do after break ups is just give him some space, but letting him know that I'm there for him (because although he says he's better without me, he's worse than ever in those times). Then after some days I try to talk to him and see if his guards are down, and continue talking to him until he feels close to me again.
I think it's a good thing that your partner accepted some space when you suggested, even with an okay and a thumbs down reaction.

Waiting is so hard, but as others say to me here, please be kind to yourself through this time and manage to take care of yourself too, you deserve it.

I hope others have better answers for you.
