Is it permissible to keep the fetus conceived through fornication and attribute it to the husband, knowing that aborting it carries the risk of the matter being exposed?

Adultery is a grave sin, and abortion is another crime, even if the pregnancy resulted from it. Repentance is possible through abandoning the sin, regretting it, and resolving not to return to it. Secrecy is obligatory; one must not publicize it. You must repent immediately and avoid abortion, conceal your matter, and the pregnancy will be legally attributed to your husband.