Husband left but we are now in limbo

[Kate56]

My husband and I had a very lovely, close relationship for 2 years. He then began secretly meeting an ex FWB for coffee and a chat. While my dad was in hospital dying, he escalated this to sexual texts and a massage. He then made sure I would see the texts and stop it going any further. Following this he had counselling and we worked through this. Suring this time, he would get upset discussing what had happened and say he was leaving. This would be quickly followed by tears and that he was desperate to stay. He really struggles accepting responsibility. We worked through things and the last 18 months through lockdown etc have been calm.
Three weeks ago his sister sent me a text saying she could not accept something I had sent her and was blocking my number. When I asked my husband about this, he said that he had been discussing leaving me for three months with her. He gave several minor reasons for this ( all tiny things you would never leave a relationship for). He showed me the messages and she has been really encouraging him to leave and he sounds uncertain. She is very lonely and relied on him a lot when he was single. She is also very self centred. After this he said he didn't  want to be with me as we haven't  had a family. I have had several distressing miscarriages over our marriage.
As this was a hurtful statement I left and went to a family member, expecting he would ring and apologise. Instead he went to a divorce lawyer and told me to get advice. He then had a breakdown at work, wrote a suicide letter which he burned and has been referred for emergency therapy. Likely assessment is BDP.
Since then it has been a whirlwind. He is now certain divorce would be a mistake and suggested a 4 week break, but isn't
making any real moves to improve things. He is living at his sisters but coming home to work while I am out. One day he is leaving and doesn't  love me, the next he adores me and is desperate to work on things, then another day he loves me but needs space.
Is there anyway to sort this out? I am working with a therapist and she has asked me find space to think about the enormity of what he would need to work through to get to a healthier relationship and has suggested I think of ending things myself. I know I would be ok if I did this and I have good support network. However, I feel awful just thinking of doing this as I really do love him. Is there any possibility that I can adapt and not take his hurtful comments and indecision personally? I know this isn't a healthy relationship, but is it manageable?

[RELATIONSHIP PROBLEM SOLVING]

RELATIONSHIP PROBLEM SOLVING This is a high level discussion board for solving ongoing, day-to-day relationship conflicts. Members are welcomed to express frustration but must seek constructive solutions to problems. This is not a place for relationship "stay" or "leave" discussions. Please read the specific guidelines for this group.

[Cat Familiar]

Sometimes it takes some time to see the full dimensionality of a relationship with a BPD partner. The “honeymoon phase” is just that, and with the grief of letting that time go, we find clarity of who we are in relationship with.

You are getting a glimpse of what life is like with him as your partner. It’s definitely possible to improve some issues with communication, but what he has shown you will always be a component of your life with him.

Whether you stay or go, we can help you with some of the issues that are troubling.

[Kate56]

Thanks Cat. We had a conversation today and I used some of the communication tools which helped and reduced drama. He said a lot of things about finding it difficult to accept love, reacting from his emotions and so saying things he doesn't mean, also not feeling he is able to speak up what he thinks himself so following what others say instead. One of his sisters has never liked me (or anyone) and has been pushing for him to leave as then he can help her more as she is lonely.
No decisions made yet, but glad that he is willing to work on things and recognises things would be hard if we stay together as he works on himself. That helps me to think about how the relationship might be going forward.
I am going to try to make sure I look after myself too. I have my own therapist, who I went to when he left and a good support network. I am going to get back doing some of things I enjoy too.
It also helps to be here with others in similar situations.