He sounds like he has a lot of responsibilities and in some ways that's a good thing. Gives you time to work on yourself.
He has chosen to be with you despite how busy he is, I would take this as a positive. Unlike many I don't think feeding into your needs is always healthy.
More importantly, how does he behave when he is around you? Is he loving, engaged and present? If so I strongly advise seeing someone to help you address your insecurities.
Are you working, what do you do during the day to keep busy?
Maybe you could ask if he could send a text during lunch, or maybe a quick call.

Not directed at you OP I just want to add,...

....This is the one thing I hate about the mobile phone generation. Everyone requires immediate responses to their needs and anxieties.

Once upon a time you just had to wait til they got home.
We forget the world won't end of we have to wait a couple of hours.