Hi Winston26 and Welcome!
I'm sorry to hear your concern and confusion over this and you're in the right place to gain some perspective. It must have hurt to feel in limbo as he said he wished to get better and resume a healthier relationship, to then being told that friendship is all he could offer. How do you feel about just being friends? Has he sought a diagnosis and treatment?
The posts of others here will give you some idea that you're far from alone in your questions and you'll see there are some similarities in types of behaviours that are experienced generally. Could you tell us a little more background to your question? When you refer to cycles is this in regards to him having other relationships since the two of you split up?
A pwBPD has very overwhelming fears of abandonment and engulfment. So this can create that push/pull dynamic that you describe, where he doesn't want to resume the relationship yet doesn't want you out of his life. It is tough to be on the receiving end of this and I can understand your worries about whether his feelings towards you are genuine. It's likely they are, however it sounds like he has maladaptive coping methods for his overwhelming emotions. This is a great article on how a BPD r/s evolves. I'd be interested to know if you feel there are any similarities here that you recognise to the types of behaviour you've experienced with your ex? I found it really helpful in understanding the drivers behind my ex's behaviour within the r/s.
https://bpdfamily.com/content/how-borderline-relationship-evolvesKeep reading the other articles and lessons to the right of the board as these are designed to help you work through what you're dealing with and to come to terms with this. Caring for someone who is disordered is very difficult emotionally and we understand here what that is like, so post and share all you need to and we'll be listening.
Love and light x