I understand being watched because you are the only black person in your department... it's like they are waiting to see if you mess up, or if you do something else they categorize us as being the type to do. I couldn't STAND that! If I'm 5 minutes late everybody notices, but if Jessica is 30 minutes late, it's no biggie.
Anyways, just because you are the only black person, doesn't mean you need to stifle your sense of style for them. To me, coloring your hair is a subtle gesture of your creativity. You can still be professional with your hair colored that way. It would be different if you had gone into the red colors, like how some women have the burgandy looking color mixed in their hair...
Besides, it's done and can't be covered up now! It does look good, and if you naturally have light hair anyway, then keep it moving! I'm sure hubby only has your best interest at heart, but I think on this one, too much worrying about something of this nature is not necessary.
Work it Diva!