Boyfriend is extremely needy all of a sudden.. what to do?

I’ll try to keep this brief. I decided to go back to school and I’ve been extremely busy with school,work, and homework. I’ve lived with my boyfriend for two years and he’s never been as needy as he is now. During finals week I decided to go study with a girlfriend of mine and he got so upset because he wanted me to study at home but he doesn’t understand that he is a distraction to me when I’m trying to study. My girlfriend thinks that he is feeling threatened because he never finished college and he’s afraid that I’ll meet someone else.

I’ve already talked to him and reassured him that I love him and that this is just something that I need to do for myself. What else can I do for him to go back to his old self and not be so insecure about us?