your boyfriend wants you to take an action that would likely be in the best interests of you both staying together?
Awful, controlling, manipulative, toxic... not really.
Ask any couple who've been together for long enough and they will tell you that there are many many points where we have to put the survival of a relationship over our own personal goals. This is a constant problem throughout most peoples relationships. Do I do what is best for me, or best for us? They aren't always the same.
Kiddies on TSR who have never had a long-term relationships don't really understand this. They are idealistic and believe that if it's meant to be its meant to be. That has never been true. Relationships that survive, survive because of continued effort, sacrifice and hard-working. Not just doing what you want, when you want, and presuming that its possible to find a relationship that perfectly fits around your plans/whims.
That means always asking 'what do I want most at the moment?' If the answer to that is your relationship. Then obviously you shouldn't go to a university far away, because the vast vast majority of relationships fail under those circumstances. If your priority is 'actually, my education and personal future plans are more important' then yes you should go.
But it's not selfish or controlling for you and your boyfriend to come up with different answers. If your answer is that your personal goals are more important - that's fine. If his is that the relationship is more important, that's fine as well. It sucks for him, because he's going to get his heart broken, but his wish to put the relationship above personal goals isn't selfish (as long as he is holding himself to the same standards) its actually the mature way to live. Your young though, you can't expect 17-20 year olds to prioritise relationships in the same way that 30 year olds do.
So in short - your not wrong to want to go and peruse your own goals. But neither is he for wanting to prioritise the future of the relationship, and wanting a partner that will do the same. The dream where you can have a relationship where both parties can do anything they want, and never have to compromise their own plans or desires for the relationship doesn't exist. It sucks, and its going to be painful for you both, but that's life. Eventually when your ready you will be in a relationship that you want to prioritise above all else, and your attitude will be different. Until then, its perfectly ok to do what you want and peruse your own plans.
Your relationship is gone though. Until your ready to put a relationship first, you will be screwed either way when these situations happen. If you go, you'll not make it. If you stay, you'll resent him, and break up eventually.
That's life for your relationships.