He gave Maughold as his place of birth in the 1851 census (which could mean Ramsey), but I think non conformist records could be your best bet.
The Lezayre marriage is on LDS film no.0106727 which can be ordered worldwide through LDS Family History centres, and would be worth viewing in the hope it has a clue. 18 is under age (21 was of age for marriage).

Sue