I can't get over the fact the guy referred to his 'maiden' name
. I've never done that and I'm female! He also prefers 'Wayne' over 'Terry'.
His boss sounds a bit of a prat, making mountains out of molehills.
What's in a name? As he says it's not unknown for men to use their wife's surname (if his marriage breaks up he can go back to using his original). He hasn't changed his name by deed poll, it's an informal arrangement.
I was still known at work by my single name after I married (my mother did same), outside most people knew me as Mrs R. When I changed jobs approx 14 years ago I decided to be Mrs R all the time, it didn't bother me or anyone else. Like you LR I gave my girls both surnames.