Anthony married Margaret (Lady) Douglas about 1719. Margaret was born before 1719; and died. [Group Sheet] [Family Chart]

Notes:

There is no firm proof of the lineage of "Lady" Margaret.. Edith A. Rudder in "My Father's Family" suggests Scottish parents. Margaret is said to have been from the Black Douglas line of Scotland, house of Drumlaurig. Grandfather might have been James 2nd, Earl of Queensbury.
Betty Kupersmith of Seattle has read she was a granddaughter of James Douglas (who was James Campbell that married a Douglas with no male descendant and assumed the heirship of Douglas with Campbell as a married name.

Only recorded proof of the wife of Anthony Haden is a deed 29 Nov 1745 when "Margaret, his wife" reliquished her right of Dower.

From "Regarding the Ancestry of Margaret Douglas", by Jack H. Thacker;The Longhunter, Vol.15, No. 3 (Autumn 1992) pp.112-116
"The purpose of this article is to clarify a longstanding mistake with regard to the forebears of Margaret Douglas, who married Anthony Haden and immigrated to Virginia early in the 18th century.
Some 10 or 12 years ago, shortly after I became involved in genealogy research, I was advised by an elderly kinswoman that this Margaret Douglas was a daughter of William Douglas, 1st Earl of March and 2nd Duke of Queensberry and his wife, Jane Hay, Countess of March. My cousin, a resident of San Francisco, did not provide proof. However, I was advised by several experienced genealogists that she was a very competent researcher and that her findings were generally sound.
Subsequently, I discovered in the 'Parochial Register of Baptisms, 1660-1725, Peebles, Scotland' a record which reads as follows: "The 9 of Apr 1701. The E of March had a daughter baptized by Mr. James Thompson, vicar of Peebles, called Margaret Douglas. Witness, Lord David Hay, Mr. William Hay of Drummowbriar, Major Archibald Douglas of the horse guard, and the Laird of Marybowe." This was intriguing because it has been family tradition since at least the early 19th century that our Margaret Douglas was "of Drumlanrig", and the Earl of March was described as "William Douglas of Drumlanrig." As a result, I continued to search for a record of this Margaret Douglas's marriage or a record of her death, but my efforts were to no avail.
Recently, however, I have received proof that Margaret Douglas, daughter of the Earl of March, was not my ancestor, Margaret Douglas, wife of Anthony Haden. Irene (Mrs. Ben H.) cook of Longview, Texas received a communication dated 22 January 1992, from the Scots Ancestral Research Society in Edinburgh which stated the following entry was found in the old parochial registers of Peebles: "Lady Margaret Douglles (sic) daughter of the Eirall (sic) of March was buried the 23 of June 1705." Thus, this Margaret Douglas died at age 4.
We are indebted to Mrs. Cook who carried on extended correspondence and incurred not a little expense to obtain this information.
It now becomes the responsibility of us who are descendants of Margaret Douglas Haden to renew efforts to determine her parentage.
Just as there is some scant evidence of a John Haden who lived in King & Queen and then King William County beginning a few years prior to 1700, there is also evidence he had a neighbor named William Douglas. [They are both listed in the 1704 rent rolls in King William which had just been formed out of King & Queen.] This is intriguing to say the least. I have long believed that Anthony and Margaret were not immigrants of their familes but were both likely born right there in Virginia. Of course the records of King & Queen and King William are practically all destroyed so further evidence is simply not available.