A nonchalant couple.
The definition of nonchalant is not showing interest.
An example of nonchalant is the response "whatever."
without warmth or enthusiasm; showing cool lack of concern; casually indifferent
Origin of nonchalantFrench ; from non (L non), not + chaloir, to care for ; from Classical Latin calere, to be warm or ardent: see calorie
Casually unconcerned or indifferent. See Synonyms at cool.
Origin of nonchalantFrench, from Old French, present participle of nonchaloir, to be unconcerned : non-, non- + chaloir, to cause concern to (from Latin cal&emacron;re, to be warm, heat up; see kel&schwa;-1 in Indo-European roots).
(comparative more nonchalant, superlative most nonchalant)