Hi Margaret,
Any chance he was in the army?
My ggrfather born in london was also married in Dublin in 1899, he was stationed in Dublin with the Bedfordshire regt at the time, and was in India when the 91 census was taken. If you have an address for Dublin you could check the 1901 census and that might give you a clue, although my ggf was posted to South Africa from Dublin in Dec 1899 and was there until 1902.
Runey