Is it permissible for my husband to take me back after the third divorce, which I requested from him and which occurred in the presence of two witnesses, knowing that one of the pronouncements of divorce was counted as an oath and its expiation is feeding ten poor people?

Scholars differ concerning the ruling on swearing by divorce and making it conditional. The majority of them hold that divorce occurs absolutely upon breaking the oath. However, Sheikh al-Islam Ibn Taymiyyah is of the opinion that swearing by divorce with the intention of emphasis, prevention, or incitement does not lead to divorce; rather, the one who swears must pay an expiation for breaking an oath (kaffarat yamin). If the second divorce was of this type, and trustworthy scholars have given a fatwa that it does not occur and that an expiation for breaking an oath is due, then there is no harm in adopting their view. Your husband may take you back as long as he has not completed three divorces. However, if your husband sought a fatwa from someone whose knowledge is not reliable, he must consult trustworthy scholars.