From Longman Dictionary of Contemporary Englishdalliancedal‧li‧ance /ˈdæliəns/ noun [countable, uncountable] literary RELATIONSHIPa romantic or sexual relationship between two people that is not considered serious SYN fling
Examples from the Corpus
dalliance• It's reasonable to hope a wife could manage to overlook a casual, brief dalliance.• Did they have time for dalliance?• Nor does he inflate the importance of a Platonic heterosexual dalliance.• But he did not feel that she looked upon their amorous exchanges as more than innocent dalliance.• Some relationships were no doubt mere dalliances, but one woman he appears to have had deeper feelings for.• The man had escape on his mind, not dalliance.• He tenderly can deflower a virgin, endlessly pursue a stunning model and still have time for a few other dalliances. 