Tax system discriminates against the separated

I doubt any political party knows those whose marriages/relationships have broken down are discriminated against in the matter of the taxation of maintenance payments.
The payer of the maintenance receives tax relief and the person receiving it (usually a woman and often a mother) is taxed on it. That is fair enough. But it is not fair the income tax and PRSI applied is greater than that applied to other citizens with the same income but from another source.