Who is name goes first on an envelope the husbands or the wifes?

Does Husband Or Wife Go First On Personal Stationary:

• In most countries and with regards to the norm it is usually the husbands name or prefix that goes on first... It's better to put Mr. & Mrs. Smith (for example) for formal stationery than you're full names... but if it is an informal thing you are sending to family and friends then it would be Adam & Eve Smith.

• Additional Information: If the husband and wife have independent friends or, they are writing a note to a member of a club they belong too it is socially correct to also have their own name 'Adam Smith' or 'Eve Smith on their own personal stationery.