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.
Islam urged the Muslims to keep good relationships and friendship between them. Allaah says (what means): {The believers are but brothers, so make settlement between your brothers. And fear Allaah that you may receive mercy.} [Quran 49:10]
Moreover, the Prophet said: "The believers in their natural kindness, compassion and sympathy are just like one body, when one of the limbs suffers, the whole body responds to it with wakefulness and fever." [Muslim]
For this, Islam has legislated many matters like spreading Salaam, visiting the sick, exchanging gifts and so on.
On the contrary, Islam forbade cutting relations with another Muslim without a sound valid reason. The Prophet said: "The doors of Paradise open on Mondays and Thursdays; every servant that does not associate anything to Allaah will be forgiven, except a man who has enmity and disputes with his Muslim brother, and Allaah says: "Delay them until they reconcile, delay them until they reconcile." [Muslim]
If they are related, then the matter is of great importance and more serious. You should know that life is scarcely free from problems so a person has to be reasonable and wise when they occur. Indeed you did well by being keen on keeping good relations with that woman, and this is the behavior of a believer.
So we advise you to reconcile between yourselves, and each party has to renounce some of their rights, acting according to the saying of the Prophet : "The best of them is the one who starts saying Salaam." [Al-Bukhari and Muslim]
First, you have to seek the help of Allaah and then the help of relatives or whoever you think might reconcile between yourselves and remind them about some of the statements that we have previously stated, lest this dispute would lead to unpleasant consequences for the children and lead them to cut relations between themselves.
May Allaah rectify the matter between yourselves. So if this is achieved, then all perfect Praise be to Allaah, otherwise you would have at least done your duty and you are no longer held accountable in this matter, Allaah willing.
Allaah Knows best.