Thank you so much. This is so helpful to know! Based on his past choices and our dynamic I do believe this applies to him. Further, I know that he can talk in a very honest and literal way (some things I love about him), but I wasn't sure about this moment because it was indeed difficult to understand for me. Most people I know (including myself) would have responded differently. Therefore, the moment kept bothering me, even though I wanted and tried to simply trust him on his words so much. It's nice and comforing to know that his response actually makes perfect sense to a lot people who also don't see the future and who would perhaps even have responded in the same way, without that nesseceraily having to be concering/mean something bad.I think there are times when it is more useful to hear what is being actually said, rather than what it might be interpreted as meaning. In this instance, it seems quite likely to me that when he admitted that he did not see a future with you, that he actually meant exactly that, and not anything else.
As difficult as it is for most NT people to understand, there are many ND people who have little or no capability to project themselves into the future - or indeed any unknown. There is a skill required to do this, which as I know myself, can simply not be there at all, or be very limited in nature.
The fact he has no sense of what he wants for the future would tend to suggest this, so the question itself is so open-ended and lacking in framework to judge by, that there isn't an answer clear enough to give. Add to that the additional pressure of what answer you would see as right and what might be the wrong thing, and the most likely response to the question is silence.
It also seems to me that he told you how he perceives the problem, that the relationship is 'too unstable'. Since this was the core of his response, that's the question that really needs to be addressed, and whether he sees a future for the two of you is actually a tangent which takes you away from the crux of it.
My suggestion is to go back to that issue, and ask him in what ways the relationship seems too unstable, and for suggestions as to how it could be stabilized better. What you, and he, can do to establish something that is more rewarding for you both.
It's only when you both know the answers to this and agree what ways you can move forward, that either of you can really and realistically have a sense of whether the future can be together or not.
We already talked a little bit about this unstability. A few things that were discussed, were things we disagreed on (and how problematic this was in our opinion), stuff I could work on (managing my emotions, way of communicating), and the agreement that he would try to let me know sooner. For now we will work on these things and were planning on letting the topic rest for a while. It's probably a good idea to bring it up again some time in the future to reevaluate. Thank you for your insight!