Alpha Beta, they couldn't venture too far from that for their alternate show. Hence A Third, Laura Jacqmin's look at modern marriage and how the reality of polyamorous relationships stacks up against the fantasy. After six years of marriage Paul (Jeremy Legat) and Allison (Asha Reid) are still in love and still attracted to each other, but want to pre-empt the seven-year itch and think threesomes - with very strict rules - are the answer. They find Jay (Will Alexander,) who's been "a third" many times before on Craigslist, and have a successful evening with him; next they go to a lesbian club night, where they convince Mariella (Lucy Roslyn) to join them. Not sure if they want to continue with the open relationship, the couple stop contacting both of them.
But Jay and Mariella have both become attached to the couple and don't want things to end here; so they get together to propose something new for Paul and Allison to try out with them.
Sometimes the alternate show that only plays a handful of performances at the Finborough is better than the main production, and this is the case here. Director Josh Roche has found an unusual, understated rhythm to Jacqmin's writing that gives the play a unique identity and - with the audience still sitting around the living room and dining table - has a heightened feel of us encroaching on these people's private moments. Of course this is apt enough as this is a story about a couple inviting strangers into their most private places.
I'm not sure about the actors sometimes moving audience members from their seats, a conceit that seems like it comes out of a much less naturalistic production; and I'm not convinced we see why Jay and especially Mariella would become quite as obsessed with Paul and Allison as they do. But I found little else to fault with A Third, which has a nice line in humour ("My name's Jay, like the letter... only with more letters after it") as well as gentle drama which, refreshingly, doesn't go in for histrionics.
It's also sexy - Alexander being ridiculously good-looking doesn't hurt - including a funny scene of the quartet playing strip Harry Potter trivia. The show's even, measured pace could have resulted in something very dull but instead makes for an intensity that's maintained throughout.
A Third by Laura Jacqmin is booking in repertory until the 20th of July at the Finborough Theatre.
Running time: 1 hour 45 minutes straight through.