Here are a few valuable life lessons to be gathered from the new six-part series Adultery, which is about adultery.

One, don’t bother.

Two, if you do bother, don’t do it with the father of your son’s girlfriend or the mother of your daughter’s boyfriend.

Three, if you do mess around with the father of your son’s girlfriend or the mother of your daughter’s boyfriend, make sure nobody’s got anyone saved in their phone under the moniker “Dickhead Dave”. Because he is not going to help matters.

But Beth (Romola Garai, far too good for this by-the-numbers effort from Danny Brocklehurst) is a bored, beleaguered fortysomething mother of two who has recently lost the personal-trainer business she was passionate about. She is also mourning the loss of her best friend whose husband is facing an assault charge. And Tom (Dominic Cooper, ditto) is a fortysomething father and GP, married to charity fundraiser Hannah (Shelley Conn) who has been struggling with her mental health for a bit.…