Most Helpful Guy
From a relationship coaching lens, I have a very basic belief: We make time for what matters. Busy or not, if you were a priority for him, he would've found the time.
As well, when he said to you, "I've been realizing that a beautiful girl with an amazing personality deserves more time dedicated to solely her and I can't keep up with that", I thought, that's sweet but it's also very often used to cushion the blow.
All to say, I don't think a lack of time is a weak reason to break up with someone, it just says a lot about what his real priorities were/are. I must say, this isn't something that you should worry about. I know it's easy for me to say that because I'm not in your shoes but this is not something that you can control. Not only that, you don't want to chase someone who isn't chasing you. In this case, he ended it and the more time you focus on the 'why' and the fact that you two could've compromised, the less time you're focused on moving forward. And by the way, what's to compromise for someone that already wasn't spending enough time with you? Think about that.
Most Helpful Girl
When it comes to things like that, they are ALL excuses. Being w/someone will not always be easy, even committed people get busy, as do married people, but they don't just leave. As a couple you work things out, not bail as the 1st sign of an issue.