I don’t think it’s necessarily that he’s insecure about you getting a college degree.
When my wife went back to school (in her late 20’s as well) it meant we both needed to move, I needed to work as much as possible, and she needed to study. We both understood that going in, we both knew it was a short term sacrifice for our combined long term goals. No problems there.
What I didn’t understand is how completely school would dominate her thoughts even when she was away. If she wasn’t actively in school or studying it seems like she was worrying or stressed out about the next day’s test, quiz, or presentation. It was a demanding two year program and any down time she had was either spent sleeping or decompressing with bad TV or a book. There wasn’t a lot of time left for us and she couldn’t seem to “get away” in her mind.
After 6 months or so it seemed to me like I’d gone from #1 in her life to somewhere between #13 (washing her hair) and #15 (the latest episodes on DVR). I often felt like I was a distraction rather than being a key part of her life. I completely supported her choice to go back, but my confidence in “us” just kept getting eroded by so many things being put in front of our relationship. Maybe this made me appear needy, I’m not sure, but I felt like I had a very busy roommate living with me instead of the girl I loved.
Eventually we figured out we needed to reserve time for real conversation and reconnecting.
For us that meant getting out of the house for dinner a few nights a week. It was a lot easier for her to leave stuff behind if we left the house, so we’d go get sandwiches or something and sit down for 30 minutes or so. That way she wasn’t killing a huge amount of time (and stressing about it) but we could talk and have more connection than just the shared living arrangements.
The other thing was Friday nights were always time to hang out together and do something special if we had a little extra cash. It’s an easy night because you still have the whole weekend if something is due on Monday and you’re usually ready to let down a bit anyway after a full week. Having it scheduled gave her “permission” in her mind to let go and not worry about whatever was coming up next in school.
It made a huge difference and really it was just about showing a little effort for the relationship (I’m not saying you’re not, just sharing my experience). I can’t say for sure if it made school any easier for her, but it made getting up and going to work a lot easier for me knowing we were both working towards the same goal.
I’m not saying your situation is the same, but I felt there could be some parallels and hopefully our experience might shed some light on what your boyfriend is thinking and possibly point to some solutions.