I used to call once a week and e-mail twice a week, my first tour.
My second tour, I was not in such a great place mentally, and calling home made it worse, so I only called once a month or so. I still e-mailed several times a week though.
That was Iraq. And that was my mission. Your boyfriend is going to a different country, and has a completely different mission. He will be out on convoys more than I was, certainly, and that can rule out him contacting you at all that day.
The situation is too variable to answer your question. You will hear from him. Just not every day.