The Alan Ayckbourn play, The Norman Conquests, and its televised performance (in 1977 and available on DVD) make for a magnificent experience.
This is actually a triptych of plays featuring six British characters, all but one of them related. Many a fault, or sin, is manifest among them; many a sad moment arises. Norman is an assistant librarian and a great, rather promiscuous, lover unhappily married to a woman he nevertheless yearns for. He conducts an affair with Annie, who inwardly recoils from such a feckless man but is subtly resisted by the naïve chap, Tom, of whom she is fond. Matronly Sarah nags her husband Reg mercilessly, but is disappointed enough with her marriage to enjoy the odd attentions of the Norman she deplores.
A serious play, then, but, as everyone knows, Ayckbourn writes comedies—which is why his plays get mounted—so there is no depressing content. The cast is superlative. Tom Conti (Norman), for example, is nearly startling in his nuances. Penelope Wilton was as good an actress in her thirties as she is now, and had better material in Norman than she does in Downton Abbey. As Annie, she can be fiery but yearningly sensitive as well.
Also, I’d like to say this: Again, it is a 1977 production, and it’s refreshing to see a show which never questions whether a character who is less than a he-man, e.g. Norman, is genuinely heterosexual (instead of, say, bisexual). Behind such questioning is the wish to see homosexuality as more pervasive than it really is. No, The Norman Conquests is a strictly heterosexual comedy.