On 8 August 1814, Ponsonby married Lady Barbara Ashley-Cooper (the only daughter and heir of the 5th Earl of Shaftesbury and a co-heir of the medieval Barony of Mauley, 1789–1844).
ˌɔn ˈeɪt ˈɔːɡəst wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd fˈoːɹtiːn, pˈɑːnsɑːnbi mˈæɹid lˈeɪdi bˈɑːɹbɚɹə ˈæʃlikˈuːpɚ ðɪ ˈoʊnli dˈɔːɾɚ ænd ˈɛɹ ʌvðə fˈɪfθ ˈɜːl ʌv ʃˈæftsbɛɹi ænd ɐ kˈoʊˈɛɹ ʌvðə mˈɛdɪˌiːvəl bˈæɹəni ʌv mˈɔːli, wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd ˈeɪɾi nˈaɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd fˈoːɹɾi fˈoːɹ.