<human>: So lately my boyfriend has been wondering what it's like to be independent again and mentioned to me that it would be nice to know if there was someone out there that was better suited for him. This has been his first relationship, and my fourth. About half a year ago he mentioned something similar, about being afraid of commitment, but we talked about it for a long time and he seemed to change his mind (I made sure that I wasn't trying to deliberately bully him into changing his mind), and everything went well for a while after.

Admittedly, while we share a lot of fundamental values, we don't always have the same hobbies and we have very different tastes in certain things. But we've never really argued, and we've always treated each other very well. It's been hard to always ignite sparks in the relationship, mostly because my studies are very demanding  and we don't always have time for each other. But we do have fun experiences and fun times together. 

I was really shocked to hear him admit this to me again, especially when I thought that we were slowly improving things with the relationship (like trying to have similar hobbies, etc.). He didn't seem to be particularly unhappy with anything in the relationship, but just doesn't want to end up marrying me and having regrets. 
Personally, I've never really considered marriage just because it seems like it's such a long way off, and there are so many factors that can lead into us breaking up in the long run. I'm a little frustrated that this might just end up being the reason why we break up. I know the right thing would be to just let him go, but at the moment it doesn't seem like he's going to take any action any time soon. Advice or thoughts, please and thanks.

Condense the text into a few key points
<bot>: Boyfriend is having what might be grass-is-greener syndrome for the second time again, we haven't broken up but I'm afraid we might be heading towards one.