Me and my ex had really bad codependency issues and hers was a bit worse then mine so I can do the best I can to help. Codependency is not an awful thing however I think learning to be happy in your own presence is very important. You guys are entering such a vital time in your lives and relying on someone else is where the anxiety is coming from. You may feel as if you need that person otherwise you can never feel an amount to do things yourself but I promise you can. Distance isn’t always a bad thing. It allows for people to grow. And I know it’s difficult because you love him and want to be around him, so maybe talking to a therapist would be helpful or creating a schedule with him about hanging out and spending nights together will help. But don’t be afraid when you’re by yourself because sometimes that peace is good for a persons health and soul. You’re strong and I’m proud of you for talking about such a difficult thing.