merflk:

the encyclopedia of celtic mythology and folklore:  
 Labhraidh Luathlam ar Cleb

Ruler of MAG MELL, the “plain of honey” where the trees were always loaded down with magical fruit and vats of mead could never be emptied, Labhraidh arranged for the hero CÚCHULAINN to spend time with Labhraidh’s wife’s sister, the lovely FAIRY QUEEN FAND. In return for this dalliance, Cúchulainn had to fight and defeat three warriors who were troubling Labhraidh. This bargain set in motion a love triangle, because Fnd was the only companion who tempted Cúchulainn to break faith with his wife, the peerless EMER.