The Mashaikh of Tasawwuf have stated that jealousy is when a person is upset with the success of another and wishes for the others blessing to end. These mashaikh have broken it further down to degrees - the 1st degree being a natural jelousy. This level of jelousy they have deemed to be excused on man, not sinful. Only when the person acts on jelousy then it is a sin. Jelousy is based upon takabbur, arrogance, and ghuroor, falsehood. It is impossible for us to even entertain that the mothers of the believers (ra) had any of these evil qualities in them. There is a difference between "I wish he leaves her" and "I wish I could spend more time with him."