Whos right?

me and my fiancee had a bet..he betted that he could go 2 weeks without . the prize....50 quid and either he sings at our wedding with me or i wash and hoover his car. just now i won but hes refusing to pay out saying he didnt know it was still on cos we had a argument the other day over something else. a bets still a bet tho..am i right?