I was pregnanat in the second month and my husband had forced me to have an abortion. What is the rule of Islam in this case.

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 Islam as it is an aggression against a life that could have become a good person who worships Allah. The prohibition becomes more emphatic if the abortion was done after life was insufflated in the fetus as this is killing a life without a right to do so. In this case, abortion is strictly prohibited with or without permission of the husband, and regardless of whether the husband forces the wife or not. She should not do such an act as long as she can. Aborting is not lawful except if the fetus represents a certain danger to the life of the mother, and this is certified by trustworthy, competent doctors.
Now, since this woman aborted her fetus without dire necessity and since life was already insufflated in the fetus, she has to do the following. First, she must repent to Allah, multiply Istighfar and good deeds seeking the forgiveness of Allah. Second, since the fetus was more than 40 days old (he was formed) she must pay the Diya (blood money). She does not inherit from this money and she must pay to the other inheritors of this fetus unless they forgive her by giving up their rights. Third, she should fast two consecutive months as expiation for killing a human being.
As for her husband, he should repent to Allah from this crime multiplying Istighfar. But he is not required to pay Diya as he did not directly cause the abortion.
Allah knows best.