You're absolutely right that your dreams are both understandable but different. It's quite refreshing to read someone who's mature enough to recognise this instead of wanting agreement that the partner to be *wrong* for their choices.
I'm not sure this is meant to be. While his dreams are admirable, I do think that in order to work well a relationship needs to be a higher priority. Also, you're talking a lot of self sacrifice for his dreams - but I'm seeing very little compromise on his part. He talks about how he'd regret for the rest of his life if he didn't pursue his dreams...but I'm not seeing that he'd regret for the rest of his life if his pursuit of career ended this relationship.
If you were to stay on, I'd like to think he'd put the relationship and his career on equal footing. I'd want to see him trying to figure out how to be successful at both work and love. And to be honest, I'm dubious that he really would be around for the kids.... I find it difficult to imagine that someone with such career drive would pull back in 10 years.
Lastly, be wary of someone who wants you to put your childbearing on hold till you're in your 30s. Fertility wise, you're so much better off following your own timeline. How would you feel if you waited till your 30s and then found that you had trouble conceiving?
Only you can make the decision....so I guess I just want to reassure you that your concerns have much merit. Don't ignore your gut feeling. Also, you're still young - if you did end things, you've got plenty of time to meet someone who's more suited to you.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.