3. If he gets a phone call, he always goes somewhere else to take it
“If it’s something urgent to do with work, he could just answer the call here, and if it’s a friend he could message them back later.” It may be that he doesn’t want his girlfriend to hear him talking with whoever’s on the other end of the line. Tell him, “If you get a call from work, you don’t have to leave the room to take it,” and if he leaves to answer the phone you’ll know it has nothing to do with his job.