Is it obligatory to maintain ties of kinship with those related through fosterage, and how can a wife convince her husband who refuses to do so?

It is recommended to maintain ties with and honor the kin from fosterage, but it is not obligatory as is the case with blood relatives. The husband should be reminded of the virtue of this, and if he grants his wife permission, then praise be to Allah. However, if he refuses, the wife is not permitted to disobey him, as maintaining ties with this type of kin is not obligatory. Even the rights of blood relatives are deferred to the rights of the husband.