Mr Blair is no wife-batterer. However, anyone hearing his words to the TUC conference in Brighton yesterday might easily have accused him of mental torture. True, he did not confess bluntly: "I'm sorry, I don't love you." But it might have been better if he had. Instead, he toyed with the delegates' emotions by challenging their most deeply held tenets and, implicitly, questioning their very role.
Ask any trade unionist in Brighton what the unions are there for, and somewhere in their reply will be the notion that they are about protecting their members' interests. These interests, it will be contended, do not always coincide with those of the bosses - the owners and managers of the businesses they work in. The more old-fashioned shop stewards will talk about the class struggle, about securing wages at the expense of profits, and all the rest of it. In the political sphere, for decades Labour governments' job was to promote workers' interests and bolster union power.
Mr Blair does not see things like that. He said: "It's completely absurd to suggest that supporting business means we're not supporting employment or we don't support trade unions. Let me spell it out: in backing business we're supporting employees and employment."
There we are then: no conflict. The interests of bosses and workers are as one.
Mr Blair is right to expose the intellectual bankruptcy of confrontation and industrial militancy. And the unions would do well to start thinking of the benefits of partnership with employers and about how they can really help their individual members - by offering 24-hour legal advice on employment rights, victimisation and discrimination, for example. Two few unions are making practical progress here.
Yet, despite Mr Blair's tough (but fair) words, and despite his political philandering with an assortment of millionaires whom the average Unison activist would find loathsome, the unions still put up with things. They may feel that they have no alternative; although they get little from New Labour, it is at least something, and better than having the Tories in power.
But this is a desperately timid, bleak outlook. Trade unionists should know by now that they will get nothing from New Labour ministers that those ministers are not inclined to offer in any case (code: "fairness not favours"). They should recognise that the electoral alliance plays badly and does neither side any good. The unions should also see that not even New Labour will be in power for ever. It is time for them to stop relying on a traditional, and now indifferent, partner, and try some new relationships - with other parties and organisations and, indeed, the public. Who knows, they might enjoy life after divorce.