On 27 Aug 1763 [his father] John Wallop 2nd Earl Portsmouth (age 21) and [his mother] Urania Fellowes (age 21) were married.

On 30 Jan 1795 Newton Wallop aka Fellowes 4th Earl of Portsmouth (age 22) and Frances Sherard were married. He the son of John Wallop 2nd Earl Portsmouth (age 52) and Urania Fellowes (age 53).

On 19 Nov 1799 [his brother] John Wallop 3rd Earl Portsmouth (age 31) and Grace Norton Countess Portsmouth (age 47) were married. She by marriage Countess Portsmouth. She the sister of one of his trustees William Norton 2nd Baron Grantley (age 57). She being forty-seven years old at the time of the marriage was considered unlikely to have children which his brother Newton Wallop aka Fellowes 4th Earl of Portsmouth (age 27) considered desriable given John's mental condition. He the son of John Wallop 2nd Earl Portsmouth and Urania Fellowes (age 57).

On 26 May 1804 Peter King 7th Baron King (age 27) and [his future sister-in-law] Hester Fortescue Baroness King were married. She the daughter of Hugh Fortescue 1st Earl Fortescue (age 51) and Hester Granville Countess Fortescue (age 38).

On 24 Jun 1820 Newton Wallop aka Fellowes 4th Earl of Portsmouth (age 47) and Catherine Fortescue Countess Portsmouth (age 33) were married. She the daughter of Hugh Fortescue 1st Earl Fortescue (age 67) and Hester Granville Countess Fortescue (age 54). He the son of John Wallop 2nd Earl Portsmouth and Urania Fellowes.

In or before 1824 James Hamlyn-Williams 3rd Baronet (age 34) and [his sister-in-law] Mary Fortescue (age 31) were married. She the daughter of Hugh Fortescue 1st Earl Fortescue (age 70) and Hester Granville Countess Fortescue (age 58).

On 26 Oct 1847 [his son-in-law] Ralph Merrik Leeke of Longford Hall, Shropshire (age 34) and [his daughter] Hester Urania Fellowes (age 25) were married. She the daughter of Newton Wallop aka Fellowes 4th Earl of Portsmouth (age 75) and Catherine Fortescue Countess Portsmouth (age 61).

On 08 Jun 1852 [his son-in-law] Dudley Francis Fortescue (age 31) and [his daughter] Camilla Eleanor Wallop were married. She the daughter of Newton Wallop aka Fellowes 4th Earl of Portsmouth (age 79) and Catherine Fortescue Countess Portsmouth (age 65). He the son of Hugh Fortescue 2nd Earl Fortescue (age 69) and Susan Ryder. They were first cousins.

Seymour Phillips Allen of Cresselly, Pembrokeshire and [his daughter] Catherine Henrietta Fellowes were married. She the daughter of Newton Wallop aka Fellowes 4th Earl of Portsmouth and Catherine Fortescue Countess Portsmouth.