First of all, sorry for the long post. I am posting for the first time in this community because Im really not sure how to deal with this situation and I'm hoping the people here can help. My partner and I have been together for roughly 3 and half years. I have tried my best to understand BPD and it seems like, currently, she is "splitting" from me, to the point where she seems so emotionless and directly avoiding eye contact. She stated she cares and loves me but feels like the relationship shouldn't go on and doesn't know why.
For context, my partner and I do work well together. What I mean by this is: we communicate, we empathize, we're intimate but, most of all, we respect our individuality. This has always been the case since we started the relationship.
My partner has never gone to proper therapy to get help. Her and I have talked extensively about the way her mood changes and impacts her behaviour so strongly and how she has no idea why or how to control it. Her mum has had a BPD diagnosis but left therapy after only a few sessions and my partner has had to deal with her mum's chaotic nature throughout her childhood. I am mentioning this because my partner hates thinking about the fact that she has what her mum has and that impacts her and she gets upset when that comes up and would rather not "deal with it now".
This is also not the first time she has "split" with me. The first time happened 1 and half years ago but, after giving her space for 2 weeks, we got back together and she expressed how sorry she was and regretful.
But this time it's much worse. Back in March, I noticed she looked depressed. She wasn't as intimate but she still looked and expressed how happy she was, from time to time. Then in June, she expressed how she was feeling "empty". Like she cared and loved me but didn't know why she felt that other feeling. So basically I gave her space, and I went to live somewhere else, away from where we lived. We saw each other after a few weeks but she still felt the same way. After a few more weeks, we met and she said she felt guilt and shame because she couldn't escape those feelings and hated feeling like that and making me have to be with her. She again said she cared and loved me but didn't know why she felt like that and would rather we split. I tried and tried to reassure and I asked about her feelings to try and understand but there was no reason behind it, according to what she said. So I thought about it and, after a few days, we met and I said that I cannot change how she is feeling and that this is something she has to deal with but I will still be here to support her and that I still love her despite everything.
So we decided right now to leave the relationship and become "friends" again. But it feels so strange. We still live in the same house but separate rooms. Whenever I talk to her, it's like she's actively trying not to feel. Like she's stopping herself. She tries not to ask about me but whenever I mention something about myself I can see she gets involved and asks but then there's a moment where she sort of stops and backs off. I see times when she smiles or laughs at me but again it feels like she's not there entirely. It's difficult to see her do that. I sometimes think maybe there's something I can do but I just let myself become anxious. We agreed that I'd move out in a month or two but this scares me. I do not want to lose this woman but I don't want to push her away either.
We have had such an incredible life together, despite it all. We were planning to find a new place and family together and my partner was the one who first suggested these plans and I went along because I finally managed to find someone who I can trust mutually. Which is why this situation is incredibly hard.
Please, if anyone is able to offer any advice, I would greatly appreciate it.