Is the questioner allowed to leave the woman who claims she is pregnant by him after he repents, knowing that she has returned to her husband?

The questioner and the woman must engage in sincere repentance (tawbah nasuh) for committing a grave crime and a serious betrayal. The Prophet, peace and blessings be upon him, clarified that the greatest sin after associating partners with Allah is for a man to commit adultery with his neighbor's wife. Among the requirements of repentance is to immediately cut off all contact with the woman and not allow her to call. As for her claim of pregnancy, it is not accepted, for the child is attributed to the bed (the husband) if she is married, or to her if she is not married, and for the adulterer is the stone (i.e., rejection and disappointment).