Marc Thompson said the "hardest thing is not knowing" where his twin brother Ben is.
The 34-year-old from Haverfordwest has been missing since Saturday, after he watched Wales' Six Nations game at the Millennium Stadium.
He told our Correspondent Carole Green that this would be "very out of character" for him not to contact his family.
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Council have until today to say if the plan to merge. Minister Leighton Andrews says joining together will create "significant savings"
Mainly cloudy, with a little patchy, light rain in the southeast this afternoon. Some brighter spells in the west at times.
A largely dry, cloudy and mild night with fog patches mainly confined to higher ground. Blustery along the coast.