Before 1608 [his father] Henry Carey 1st Earl Dover (age 28) and [his mother] Judith Pelham Countess Dover (age 17) were married. They were third cousin once removed.

In 1621 Hatton Fermor of Easton Neston Northamptonshire (age 41) and [his future sister-in-law] Anne Cockayne (age 16) were married. She brought a marriage portion of £4000. The difference in their ages was 24 years. She the daughter of William Cockayne (age 60) and Mary Morris Countess Dover (age 56).

In 1623 [his future brother-in-law] Oliver St John 5th Baron St John (age 20) and Arabella Egerton Baroness St John Bletso were married. She the daughter of John Egerton 1st Earl Bridgewater (age 44) and Frances Stanley Countess Bridgewater (age 40). He the son of Oliver St John 1st Earl Bolingbroke (age 43) and Elizabeth Paulet Countess Bolingbroke. She a great x 4 granddaughter of King Henry VII of England and Ireland.

On 24 Jun 1627 [his future brother-in-law] Charles Cockayne 1st Viscount Cullen (age 24) and Mary O'Brien Viscountess Cullen (age 18) were married at Church of St Gile's in the Fields. She the daughter of Henry O'Brien 5th Earl Thomond (age 39) and Mary Brereton Countess Thomond (age 47). He the son of William Cockayne and Mary Morris Countess Dover (age 62).

After 1628 Thomas Fanshawe 1st Viscount Fanshawe (age 32) and [his future sister-in-law] Elizabeth Cockayne Viscountess Fanshawe (age 19) were married. She the daughter of William Cockayne and Mary Morris Countess Dover (age 63).

On 09 May 1628 John Carey 2nd Earl Dover (age 20) and Dorothy St John were married. She died eight weeks later. She the daughter of Oliver St John 1st Earl Bolingbroke (age 48) and Elizabeth Paulet Countess Bolingbroke. He the son of Henry Carey 1st Earl Dover (age 48) and Judith Pelham Countess Dover (age 37).

On 06 Jul 1630 [his father] Henry Carey 1st Earl Dover (age 50) and [his step-mother] Mary Morris Countess Dover (age 65) were married at St Peter le Poer, Broad Street. She by marriage Countess Dover.

On 02 Dec 1630 John Carey 2nd Earl Dover (age 22) and Abigail Cockayne Countess Dover (age 20) were married. She the daughter of William Cockayne and Mary Morris Countess Dover (age 65). He the son of Henry Carey 1st Earl Dover (age 50) and Judith Pelham Countess Dover.

In 1655 [his son-in-law] William Heveningham (age 51) and [his daughter] Mary Carey (age 24) were married. The difference in their ages was 27 years. She the daughter of John Carey 2nd Earl Dover (age 47) and Abigail Cockayne Countess Dover (age 45).

Before 1664 James Sheffield and [his sister-in-law] Jane Cockayne (age 54) were married. She the daughter of William Cockayne and Mary Morris Countess Dover. He the son of Edmund Sheffield 1st Earl Mulgrave and Mariana Irwin Countess Mulgrave.

Paulet St John and Elizabeth Vaughan were married. He the son of Oliver St John 1st Earl Bolingbroke and Elizabeth Paulet Countess Bolingbroke.

Anthony St John and Ann Keynshan were married. He the son of Oliver St John 1st Earl Bolingbroke and Elizabeth Paulet Countess Bolingbroke.