Tom Stoppard 
Real Thing [EPUB ebook] 

The play begins with Max and Charlotte, a couple whose marriage seems about to rupture. But nothing one sees on a stage is the real thing, and some things are less real than others. Charlotte is an actress who has been appearing in a play about marriage written by her husband Henry. Max, her leading man, is also married to an actress, Annie. Both marriages are at the point of rupture because Henry and Annie have fallen in love. But is it the real thing?