<human>: Can you condense the text into a few key points?

Using a throwaway because he uses Reddit.

My boyfriend and I have been together for 7 years and lived together for 5. 2 months ago, he broke up with me because he 'no longer saw a future'. He said that he loved me and didn't want this relationship to end but he had to end it if he no longer saw a future. I'm still reeling from this and finding it very difficult to deal with as in my mind we were heading towards marriage and kids and he had shown no sign that this wasn't what he wanted anymore, in fact he actively spoke about the future.

The relationship hadn't deteriorated at all, there was no signs anything was wrong, so I was completely shocked by it. I don't believe there is anyone else. I'm finding it very difficult to get closure.

My question is, if a relationship is happy and healthy (which he said it was) and you've been together a long time and made plans for the future. How does one suddenly no longer see a future? What does that actually mean? How does that happen? I'm just trying to understand the process there.
<bot>: Boyfriend ended 7 year relationship that was loving and happy because he didn't see a future anymore, how exactly does this happen?