Just be honest and open with him about it. Pretty much everyone who knows me knows I HATE being on the phone - but that I will text throughout the day.

Like - I dislike it so much that if I actually call a friend, they answer and are like "what's wrong?!" because they know I only ever call if there's a reason I need their attention ASAP. Same with if they call me - I will answer immediately because I know there must be a reason! (Once... it was a call from a friend and the convo went like this: Me: "What's wrong?!" Friend: "why haven't you replied to your texts?!?!"... me: "Your call woke me up... why, what's wrong?" friend: "It's 11am! You never sleep this late! I was worried!" me: "WOW I've been in bed 13 hours!!!")

That said.... if you just don't like being on the phone, but you know it means a lot to him? Why don't you try to surprise him with a quick phone call to say goodnight sometimes? Later at night means it's likely quiet enough that hearing isn't too difficult. Plus I'm sure it would just thrill him to hear your voice when it's initiated by you. Just let him know that maybe during work-hours isn't so cool because it's noisier? (if that's the case).