All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The fornication that both of you had committed is indeed one of the great major sins. Allaah says: (interpretation of the meaning): {And come not near the unlawful sexual intercourse. Verily it is a Faahishah (i.e. anything that transgresses its limits; a great sin) and an evil way (that leads one to Hell) unless Allaah forgives him/her.}[17: 32].
The Prophet said: "A fornicator at the time of adultery or fornication is not a believer (meaning that he does not act according to the implications of his belief).'' [Al-Bukhari and Muslim] The abortion that the woman had performed after forty days of the conception of the foetus is also forbidden, as it is killing a soul that Allaah has not permitted to be killed, therefore she has to do three things:
1. To sincerely repent to Allaah fulfilling all the conditions of repentance mentioned in Fatwa: 87993.
2. She has to expiate for the sin, and this is the opinion of Al-Hanbali and Shaafi'ee Schools. The expiation is to free a slave or to fast two consecutive months.
3. She has to pay what is worth the tenth of the blood money of the mother. The mother would not take anything from it as she is the one who caused the abortion. But it should be given to the other heirs of the fetus, like the grandmother of mother's side, or the maternal uncle and the like.
Anyway both of you have to repent to Allaah from this abominable sin which caused killing an innocent soul. You have to give up contacting this woman at once, as she is now a wife of another man. It is not one of the conditions of repentance that this woman should forgive you, because she deliberately committed this crime, so do not be preoccupied by her accusations, and stop contacting her so that you will not commit the same sin again.
Allaah knows best.