Lisa. Is your H a very social guy? If not, is it possible he uses the phone as a crutch for those moments when no one is talking to him?
I know I am guilty of that. Until I have had a few drinks, I am very shy. If he was already feeling uncomfortable because you were having so much fun, and he's a bit of an introvert, he may have turned to his phone just for lack of something better to do...?