Last Night's Viewing: Secrets of a Good Marriage with Sharon Horgan, Channel 4Africa, BBC1

They spell "weird" an odd way at Channel 4. The word actually appeared as "good" in Secrets of a Good Marriage with Sharon Horgan, in which the co-creator of Pulling notionally explored the underpinnings of an enduring marriage. She would, she told us, be "nosing about in the life of six married couples to find out" the best way to keep a marriage in good shape, and she vaguely implied that these relationships would be broadly representative of the marital state.

In fact, what she (or her researchers) had actually done was to find the quirkiest unions available – the secrets they vouchsafed either being impossible to apply to your own life (have you got an identical twin on hand, with whom you can form a ménage a quatre with another pair of monozygotic siblings?) or shudderingly undesirable, as with the soupy tantric sex couple who were served up as the first course.

"We have an absolutely mind-blowing sex life," said Roland about his shagtastic marriage to Kavida. No proof was offered for this contention, but circumstantial evidence was available in the manifestly blown condition of both of their minds and the way they spent most of the time gazing into each other's eyes in a dazed fashion. They invited Sharon to sample their early-morning routine of "sexy Pilates" (she declined) and tutored her in the art of having a sexy cup of tea (which she accepted, warily). "I'm going to ask Roland to pour the essence of himself into the tea," said Kavida, before inviting Sharon to take a sip. "Shit. Hope I don't come," she said, "Imagine how embarrassing that would be." Both Roland and Kavida were on their second marriages, which suggests that this recipe for blissful togetherness doesn't always take.

Horgan was the best thing about this – undercutting and funny and prone to sly little glances at the camera just to reassure you that she thought it was all as nuts as you did. In fact, you could say that she was the only good thing about it, since the people she went to talk to were pretty predictable in their diversions from the deep rut of marital normality (apart from the identical twins, at least).

She talked to a woman called Louella who plays away from home with the permission of her loving but un-libidinous husband (offered a choice between sex or a bacon sandwich on their wedding anniversary, he opted for the sandwich) and also met Chris and Norma, an apparently happy Brighton couple despite the 32-year disparity in their ages (when Chris first approached Norma to chat her up, she thought, "He's gonna nick me handbag"). And she met Steven, who has restored contentment to his own marriage by persuading his wife that she must defer to him in everything – a "secret" he derived from his study of McDonald's nutritional guides (I'm not kidding) and the life of lions in the wild. "We are animals!" he insisted when Horgan gently pointed out that we are more than our biology. Granted in your case, Steve, but something oinkier and less agile than a lion, I think.

Ex Africa semper aliquid novi, apparently. Though you wonder how they manage it given the saturation coverage of the continent in wildlife documentary over the past 30 years. Anyway, the good news about Africa, BBC1's new six-part series, is that they're still finding sights that stun you. This is partly down to technology. As you watch the breath of a drongo condense on the morning air or thrill to a giraffe duel, you're unwittingly admiring the latest developments in lenses and distance filming. But it's also about Africa's capaciousness as a continent. "There's nowhere on earth where wildlife puts on a greater show," said David Attenborough at the start. Odd phrase, given that none of it is aimed at us. But what a show it is anyway.

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