Half Second Cousin Twice Removed is in Second Cousin.
In 1194 Odo III Duke Burgundy (age 28) and Theresa Burgundy Duchess Burgundy (age 43) were married. She by marriage Duchess Burgundy. She the daughter of Afonso "Conqueror Founder Great" I King Portugal and Malfada Savoy Queen Consort Portugal. He the son of Hugh III Duke Burgundy and Alice Metz Duchess Burgundy. They were half second cousin twice removed. He a great x 3 grandson of King William "Conqueror" I of England. 
Around May 1225 Roger Bigod 4th Earl Norfolk (age 16) and Isabella Dunkeld Countess Norfolk (age 30) were married. She by marriage Countess Norfolk. She the daughter of William "Lion" I King Scotland and Ermengarde Beaumont Sarthe Queen Consort Scotland (age 55). He the son of Hugh Bigod 3rd Earl Norfolk and Maud Marshal Countess Norfolk and Surrey (age 31). They were half second cousin twice removed. She a great x 2 granddaughter of King Henry I "Beauclerc" England. 
On 22 Jan 1260 John Capet II Duke Brittany (age 21) and Beatrice Plantagenet (age 17) were married. She the daughter of King Henry III of England (age 52) and Eleanor of Provence Queen Consort England (age 37). He the son of John "The Red" Capet I Duke Brittany (age 42) and Blanche "Navarre" Blois Duchess Brittany (age 34). They were half second cousin twice removed. He a great x 5 grandson of King William "Conqueror" I of England. 
In 1325 Edmund of Woodstock 1st Earl Kent (age 23) and Margaret Wake Countess Kent (age 27) were married. She by marriage Countess Kent. He the son of King Edward "Longshanks" I of England and Margaret of France Queen Consort England. They were half second cousin twice removed. She a great x 3 granddaughter of King John "Lackland" of England. 
Before 04 Apr 1336 Thomas of Brotherton 1st Earl Norfolk (age 35) and Mary Brewes Countess Norfolk (age 34) were married. She by marriage Countess Norfolk. He the son of King Edward "Longshanks" I of England and Margaret of France Queen Consort England. They were half second cousin twice removed. She a great x 3 granddaughter of King John "Lackland" of England. 
After 21 Jul 1403 Thomas Camoys 1st Baron Camoys (age 52) and Elizabeth Mortimer Baroness Camoys (age 32) were married. She by marriage Baroness Camoys. The difference in their ages was 20 years. She the daughter of Edmund Mortimer 3rd Earl March, Earl Ulster and Philippa Plantagenet Countess March 5th Countess Ulster. They were half second cousin twice removed. She a great granddaughter of King Edward III of England. 
In 1460 Oliver Dudley (age 23) and Katherine Neville (age 16) were married. They were half second cousin twice removed. She a great x 2 granddaughter of King Edward III of England. 
Before 12 Oct 1475 Edward Blount 2nd Baron Mountjoy (age 11) and Anne Cobham 6th Baroness Cobham, Baroness Mountjoy and Baroness Strabolgi (age 8) were married. She by marriage Baroness Mountjoy. They were half second cousin twice removed. She a great x 3 granddaughter of King Edward III of England. 
On 25 Aug 1476 John "Cicero" Hohenzollern Elector Brandenburg (age 21) and Margaret of Thuringia (age 27) were married. He the son of Albert "Achilles" Hohenzollern Elector Brandenburg (age 61). They were half second cousin twice removed.
In 1601 Thomas "Black Tom" Butler 10th Earl Ormonde 3rd Earl Ossory (age 69) and Eleanor Barry Countess Ormonde and Ossory were married. She by marriage Countess Ormonde, Countess Ossory. He the son of James "Lame" Butler 9th Earl Ormonde 2nd Earl Ossory and Joan Fitzgerald Countess Ormonde and Ossory. They were half second cousin twice removed.
In 1624 William Wrey 2nd Baronet (age 24) and Elizabeth Chichester Lady Wrey were married. They were half second cousin twice removed.
On 13 May 1755 Duke Louis of Mecklenburg-Schwerin (age 29) and Charlotte Sophie Saxe Coburg Saalfeld (age 23) were married. He the son of Christian Ludwig II Duke of Mecklenburg-Schwerin (age 71). They were half second cousin twice removed.
On 08 Sep 1761 King George III of Great Britain and Ireland (age 23) and Charlotte Mecklenburg Strelitz Queen Consort England (age 17) were married at Chapel Royal, St James's Palace. She by marriage Queen Consort England. He the son of Frederick Louis Hanover Prince of Wales and Augusta Saxe Coburg Altenburg (age 41). They were half second cousin twice removed. He a grandson of King George II of Great Britain and Ireland.
On 21 Aug 1861 George Henry Finch (age 26) and Emily Eglantine Balfour (age 20) were married at St Peter's Church, Pimlico. They were half second cousin twice removed.
On 22 Jul 1869 Augustus Gough-Calthorpe 6th Baron Calthorpe (age 39) and Maud Augusta Louisa Duncombe (age 19) were married. The difference in their ages was 20 years. They were half second cousin twice removed.
William Dampierre and Marie of Bar were married. She the daughter of Robert of Bar 1st Duke of Bar and Marie Valois Duchess Bar. He the son of William "Rich" Dampierre I Marquis Namur and Jeanne Hainault Marquis Namur. They were half second cousin twice removed. He a great x 3 grandson of King Henry III of England. She a great x 3 granddaughter of King Edward "Longshanks" I of England. 
Henry Hastings and Ada Dunkeld were married. She the daughter of David Dunkeld 8th Earl Huntingdon and Matilda Gernon Countess Huntingdon. They were half second cousin twice removed. She a great x 3 granddaughter of King Henry I "Beauclerc" England. 
William Hay 6th Earl Erroll and Helen or Eleanor Stewart Countess Erroll and Sutherland were married. She by marriage Countess Erroll. She the daughter of John Stewart 3rd Earl Lennox and Isabel or Elizabeth Stewart Countess Lennox. He the son of William Hay 5th Earl Erroll and Elizabeth Ruthven Countess Erroll. They were half second cousin twice removed. She a great x 4 granddaughter of King Edward III of England. 
