Has he always been this way? Meaning, did he try harder to contact you when you first started dating?
I was talking to someone last night about this exact same situation. It is annoying, and was actually a deciding factor when I dumped my ex. It literally takes 4 seconds to send a text like "How's your day going?".
Keep in mind that people usually treat others the way they want to be treated. He may not text you all that often, because it's not important to him to be texted every day. It doesn't mean he's not thinking of you.
Geez.. what did we ever do before texting? I miss the good 'ol days when you were lucky to catch someone at home on the phone.
The secret of success is honesty and fair dealing. If you can fake those, you've got it made. - Groucho Marx