how do you address the envelope to the 'Lady of the house'?

It's a very old-fashioned form of address, from the days when a wife was, in law, her husband's possession. So while she would be Mary Smith to her friends and family, she would formally be known as Mrs John Smith.
If anyone ever used this archaic form with me, I wouldn't be aware of it, as my DH and I have the same first initial

Oops should say 'husbands initial'

Indinnana's explanation is correct. We secretarial students were taught all kinds of things, including the correct form of addressing envelopes to married women. We were told that the woman's first name initial was only to be used if the husband had died and she was therefore widowed.

It may have prompted early feminist thinking in me at the age of 16, when I was horrified to feel that women didn't only give up their 'maiden' name when they married but also had their first name taken away, even on their own birthday cards Needless to say, I ignored this teaching.

Always Mrs. (her initial) Bloggs.

Rats, to protocol

Same as wot iam64 said. I was taught that too. Very old fashinoned now though. I think if you addressed a young married woman like that these days she would think "WTF"!

Like Iam64, I always ignored that teaching too. Utterly ridiculous!
If I'm addressing something to a married couple, then it would be 'Mr and Mrs J Smith' because 'Mr J and Mrs A Smith' looks overly pedantic, a form I have only ever seen on a couple's joint chequebook

I recently received a letter from one small DGS which was addressed to 'Granny' which made me smile and to him that is who I am of course. The postman delivered it as the address part was correct so that was alright. DDIL had added my correct title (in brackets) as that is also who I am.
One of my friends, who recently lost her husband, was telling me how sad it makes her feel every time she receives mail without her DH initials on because now she is no longer her DH's wife, her identity is now his widow. The sadness is one aspect which had not really occurred to me before when I had changed the form of address.

I was taught that 'husband's initial' way too, along with all the other now outdated forms of address and letter endings. Nowadays I give a woman her own name, no marital title, in the Quaker tradition of equality. I'm not, but I think it's appropriate in this day and age.

I agree Nina rats to protocol. In fact if it's someone I know well I write their first and surnames eg Mrs Alice Smith. And if it's a married couple I simply write Mr & Mrs Smith, or if I'm feeling that way out Mrs & Mr Smith.

Oh dear I'm old fashioned I do Mr & Mrs F Bloggs too. I don't mind it for myself I quite like being Mrs F Bloggs.

Further to iam64's point, I think some arcane etiquette tome advised that widowed women retained their husband's initial, whereas divorcees reverted to their own (but presumably retained the surname)
Another bit of Sloane Ranger/Victorian nonsense was that invitations etc were addressed to the lady of the house (wait for it!) so that she could open them presumably in her breakfast room after the Lord and master had departed to his office in the City. You couldn't make it up!

My father being of that generation which used husband's initial once sent me a cheque made out to Mrs X Bloggs, instead of Alea Bloggs and even though it was going into our joint bank account, the bank wouldn't take it.

Nowadays my question is how to address an envelope to DD2 who, happily married for the past 3 1/2 years, retains her own surname. Even she gets into a muddle sometimes as they have a joint a/c using SIL's surname, but professionally and to her friends, she uses her "maiden" name. She has to remember which name is on her passport etc when booking flights and so on. And does anybody remember that thing of ordering your passport in your married name before your wedding, but the vicar or somebody responsible had to hold it until the deed was done?

Ah, I have just scrolled up and seen synonymous's post about her friend . The widowed/divorced distinction makes sense then. to all to whom this applies.

My mother, who is 93, still insists that the correct form of address for a married woman is Mrs (husband's initial) Smith, then if she becomes a widow it changes to Mrs (own initial) Smith. She sticks to this for herself and all younger members of the family.
It doesn't apply to me because I managed to get divorced!

My mother was proud to be addressed by my father's forename or initial. The change to her own initials after his death was upsetting for her.

Alea I sympathise with your DD, for me it's my Christian names that cause the problem. Birth and marriage certificate plus passport are N A also doctors (same practice since the day I was born)
However, not even my own mum has ever called me N I'm always known as A

Now so many couples are not married or the woman has kept her own name I feel that Mr and Mrs are as outdated as Miss or Master (this sounds like Happy Families)
I always address envelopes with just names - Jane and David Smith or Jane and David.
I wouldn't do this if addressing someone very old, who would expect the old-fashioned forms.

apricot, that's what I do, use first and last names. My mum, not a hotbed feminist at all, suggested when I married for the first time at a ridiculously young age, that I kept my maiden name. I was fairly scandalised but within weeks found I wished I had. I never felt like Mrs x X , no surprise that I didn't stay Mrs x X for long and reverted to my maiden name the week I moved out. I've stayed Ms i am, including throughout the 30 plus years I've been (happily thank goodness) married for the 2nd time. The bank have got used to it but I was astounded at a recent local Labour party meeting to be asked by our local candidate for the council election "are you two married, I notice you don't use his name".

I usually write both names in full: X & Y Smith if they use the same surname or each person's first and last name with a '&' between. And if I knew the woman first I'll put her name first. I dislike titles and think them unnecessary most of the time.

nina I have the same problem as you. During a few spells in hospital I gave up explaining and just answered to my first name, same at the doctors, dentist etc. I've spoken to lots of people of my generation who are known by their middle name.
I put the woman's initial if it's just to her and the husband's if it's to both.

Does anyone use Ms for themselves or family and friends?

I like the 'lady of the house' myself, sounds very Hyacinth.

My mother hated it if anyone addressed a letter to her with her own initial. So I still habitually address letters to married couples using the husband's initial. If I'm writing to the wife I use her own initial. With friends who aren't married I tend to just use their christian names ( eg Janet and John) because it just gets so longwinded with both surnames.

I never address anyone as Ms as I always think of dungarees and crewcuts.

I'm a ms but don't have a crew cut, or a pair of dungarees. Ms simplifies things ( usually ).

I have used Ms when writing to DD as she is still married but has reverted to her maiden name. I now just write her full name.

I was taught that only divorcees were addressed by their own initial.