Hi Ann!
Tell your husband he'll be forever enshrined in the "Dad of the Year" category for going to Disney for his children, and they'll never forget it! :-)
And who knows? I know many a Dad that came to Disney kicking and screaming, only to leave having as much fun as the children, wearing Disney Mouse ears on the head and all :-)
For your birthday, make sure you tell them before your visit that you will be celebrating your birthday while you're there. Sometimes they'll have a little something special waiting when you arrive in your resort room. Also, at any of the Parks you can pick up a free "Happy Birthday" pin (at Guest Relations) which you can where on your shirt, and get showered with "Happy Birthday's!" while you're in the Parks (the Cast members, and many of the guests, immediately identify the pins). Also, some of the table service dining restaurants may provide you with a little dessert (cupcake with candle) or something similar if you eat there.
I just have to mention that this is all at the discretion of cast members and facility, so I can't guarantee all these things, but Disney has a good track record with guests when it comes to birthdays.
May your 40th be forever memorable, and you and the family have an amazing time!