Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Abortion is forbidden in Shariah since it is an aggression against an innocent soul. The prohibition and the mistake become more severe if it is done after the soul is breathed into the fetus since it is killing an innocent soul without any legal reason. Moreover, it leads to destroy progeny if it is permitted. Hence abortion is forbidden whether it is done with the permission of the husband or without his permission. Muslim scholars permitted abortion in one case, i.e. when the continuation of the pregnancy puts the life of the mother at real danger. Thus could be decided only by reliable medical doctors.
Therefore, if this woman aborted her fetus without dire necessity as described above, she has to make sincere repentance towards Allah, ask forgiveness for what she had committed and increase her good deeds as much as possible. If she does so, probably Allah will forgive her, accept her repentance and atonement for her bad deeds.
Since the abortion was done after the human shape had formed, i.e. after forty days of pregnancy, she has to free a slave man or woman as expiation, and if she cannot then she has to pay one-tenth of the value of the blood money of the fetus' mother as reported in Saheeh al-Bukhari.
The scholars differ concerning fasting for two consecutive months. Some are of the opinion that it is compulsory as it is the expiation of killing a person. Some others are of the opinion that it is not compulsory since the Prophet (Sallallahu Alaihi wa Sallam) did not impose it in his judgement as mentioned above.
If you had ordered the woman to abort her fetus then you had committed a sin Allah Orders Us: {…Help you one another in AlBirr and AtTaqwa (virtue, righteousness and piety); but do not help one another in sin and transgression…..}[5:2].
The conditions of Tawbah are giving up the sin, feeling deep regret for the violation of Allah’s Commands and taking a firm decision not to return to the sin. The Prophet (Sallallahu Alaihi wa Sallam) said: "The repentant from his sin is just as the one who does not have any sin at all". [Ibn Majah]
Know, that we gave Fatwa on the basis that your wife aborted the fetus as you mentioned in the question. If you were responsible for the abortion then the same ruling applies to you, too. The blood money is distributed among the heirs of the fetus except the one who carried out the abortion; he/she will not inherit from him.
Allah knows best.