Showmance means the romance actors engage in for the run of a show. Once the run is over so is the romance.
荧幕恋情(showmance, show romance)是演员在戏剧表演中上演的恋情。表演结束时，恋情也随之终结。
The term originated in the theater and moved to movies and scripted television and then reality television. The term has now moved to the populace to describe any contrived romance in which people fake being in love because they have ulterior motives for doing so
A: I didn't know Anthony and Cicely were dating.
B: It's just a showmance, Cicely is just dating Anthony just to make Edgar jealous.
A showmance is a relationship which develops between performers in a play, film or television series. Though there are a number of notable cases of these kind of romances leading to lasting relationships (such as for example the marriage in June 2011 of actors Rachel Weisz and Daniel Craig, who began dating while working together on a film in the previous year), a key attribute of a showmance is that it tends to only last for the duration of the show in which the individuals work together, usually coming to an abrupt end shortly after the final episode or performance.
Showmance指影视剧中两位演员之间建立的恋爱关系，有人称为“假戏真做”。虽说这一类的恋爱关系中也有相当一部分发展成为长期稳定的恋情(比如，女星Rachel Weisz和“007”扮演者Daniel Craig在2010年因戏生情，并于2011年6月结婚)，但是，此类恋情的一个核心因素就是这段感情通常只能维持到两位演员合作的影视剧完结，一般来说，剧终以后不久，这段恋情也就戛然而止了。