A divorced spouse may demand maintenance of the other, as long as and to the extent that, from the date
1. of the divorce,
2. of the end of the care for or child-rearing of a child of the spouses or
3. of the end of training, further training or retraining, or
4. of the lapse of the prerequisites for a claim to maintenance under section 1573
onwards no gainful employment may be expected of them by reason of illness or other infirmities or weakness of their physical or mental capacity.