If it's any encouragement I was in a somewhat similar situation a year ago where I broke up with my girlfriend of 5 years. I realized I was only with her because of habit, comfort and a sense that I was her only true emotional support.
Well a year later I've grown an insane amount and am so, so happy with my decision. Also, from what I can tell my ex has grown a ton as well. That's not to say it's not extremely difficult at first, but that stage passes. After being with someone for so long, it can be a really empowering to have your life be primarily about yourself again. And there's all those things that you care about that you've put to the side to give time to your relationship, fighting, trying to resolve issues etc. Getting all that time back is fucking awesome. From everything your saying it sounds like this is a great time in your life to put the priority back on yourself.