On Tuesday afternoon this week you could have watched the unedifying spectacle of a woman, her lover and her husband shrieking abuse at each other on Ricki Lake, Channel 4's Roman circus of human folly. This included a particularly rancid shot of the presenter grinning broadly as the wife struggled to prise her wedding ring from her finger with her teeth. Last night, in Breaking Point, BBC 2's series about the work of Relate relationship- guidance counsellors, you could have seen another married couple prepared to dissect their partnership in front of an audience - starkly describing the slow deflation of love and trading grievances blow-for-blow, like exhausted fighters waiting for the deliverance of the bell. And the live question is this: are these two programmes by any chance related?

In some respects, the answer must be yes. The motives that make people watch Ricki Lake are not safely discontinuous from those that cement you to the screen during Breaking Point's doleful case histories. You might well prefer to describe the first as "prurience" and the second as "sympathy", but they form part of an unbroken spectrum of curiosity about the lives of others and it wouldn't be easy to say where one fades into the other. What's more, both programmes depend on their participants' mystifying recklessness with their own privacy, their willingness to broadcast their domestic anguish to neighbours, children, relatives and millions of strangers besides. That they are all adults, old enough to make their own mistakes, does not exempt the professionals from a duty of care about what such exposure can do.

But in several important respects there is no true kinship here. Where Ricki Lake treats hurt and rage as tradeable commodities, Breaking Point - because it unwinds over time - has a genuine interest in improvement and moderation. These are narratives of intervention, of rescue even, and they tug towards a happy ending like a dog towards a bone (the fact that this cannot always be supplied is simply a register of how hard it can be to mend a marriage, but the slightly wistful tone of some of the credit-sequence codas confirms the sense that the series wants things to get better). Where Ricki Lake wallows in the wildness of its guests, rewarding excess with whoops of approval from the studio audience, Breaking Point observes its subjects' halting attempts at communication with what feels like a pained decorum. This redeeming quality of ethical restraint is, almost by definition, going to be invisible on screen - because it consists of sequences left out or clever edits resisted. But the fact that at least one completed programme has been pulled from the run because of a change of mind by its subjects is hard evidence that principles have not been abandoned here. (It is clear, too, that the couples trust the crew - in one scene last night the wife handed a magazine article she'd been talking about over to the camera, an inclusive gesture which suggested that the film-makers had acquired the status of neutral intermediaries - that they weren't simply observing the therapy but somehow participating in it.)

Most important of all, though, is the fact that it is impossible to watch Breaking Point without the occasional inward wince - sometimes of outraged fellow-feeling, sometimes of abashed recognition. Ricki Lake parades its guests as sideshow freaks, placarded with the description of their deformity ("Slept with husband's sister on her wedding day") but, barring their exhibitionism, the people in Breaking Point are you and me; anyone, in fact, who has learnt that marriage is not a simple safety net - to be winched into place and forgotten - but rather one of life's tightropes. It means that Breaking Point is not one of those series you can watch in cosy, companionable silence with your partner - all relationships have their dry tinder, after all, and this series strikes too many sparks for viewing to be without its risks. Perhaps it's lucky that it is also quite instructive about how to stop smouldering indignation from turning into a blazing row.