So where have you got the information with the marriage date in 1868 please? is it from Family Search?
I couldn't find anything in FamilySearch about it.
I first located it on RootsIreland's index:
Date of Marriage: 12-Jun-1868
Parish / District: Drumlane
County: County Cavan
Husband
Name: William Maguire
Address: Creeny
Denomination: Roman Catholic
Occupation:
Age:
Status:
Wife
Name: Bridget Donohoe
Address: Feugh
Denomination: Roman Catholic
Occupation:
Age:
Status:
Husband's Father
Name: John Maguire
Address:
Denomination:
Occupation:
Wife's Father
Husband's Mother
Name: Mary Maguire
Address:
Denomination:
Occupation:
Wife's Father
Name: Patrick Donohoe
Address:
Denomination:
Occupation:
Wife's Mother
Name: Bridget Donohoe
Address:
Denomination:
Occupation:
Witness 1
Name: John McGannon
Witness 2
Name: Bridget Donohoe
Address:
Notes:
Then I was able to find it on NLI parish registers, page 4:
https://registers.nli.ie/registers/vtls000634855#page/4/mode/1up12 June 1868 Marriage
Groom: William Maguire, Creeny
Groom's father: John Maguire
Groom's mother: Mary Maguire
Bride: Bridget Donohoe, Feugh
Bride's father: Patrick Donohue
Bride's mother: Bridget Donohue
Witness 1: John McGannon
Witness 2: Bridget Donohue