You’re in a pickle. 😕 Your boyfriend is putting his private phone calls ahead of your concerns about his fidelity to you.
My only suggestion is to take a different tact when you discuss his secret phone calls and the phone calls you pick up where there are only “breathers” on the other line. Rather than tell him that what he’s doing is inappropriate, and acting like you’re the arbiter of what is right and what is wrong, you can tell him how it makes you feel, instead. You can tell him how vulnerable you feel, and what your fears are.
He may respond a lot better to you being soft and vulnerable than to you being adamant, shrill and “right”.
In addition, if he truly is homesick for his family and friends, something you can do to help with his problem that may avert his phone calls from old friends, is to build your social life together, here. Have parties at your home. Invite lots of men and women that you both like, and start building a home for him here.
If his family is at all able to travel, invite his family members to visit you during the holidays or at any other time, so that you can, again, build his life for him here, so he doesn’t need those other phone calls from far away, that make you so uncomfortable.
I hope that helps — please let me know. 🙂