Is it permissible to host a female friend for an overnight stay in the marital home, despite the husband's refusal, given his argument that it is forbidden and involves intermingling and temptation, even though she will be in an isolated room and will not be in seclusion with the husband?

It is permissible to host a non-mahram woman if there is no fear of temptation and no unlawful seclusion (khalwa) or mixing occurs. However, the wife must obey her husband if he refuses the hosting, as she is not allowed to permit anyone to enter his house except with his permission, due to the Prophet's (peace be upon him) saying: "And she should not allow anyone into his house except with his permission," and his saying: "And you have rights over them that they should not allow anyone whom you dislike onto your bedding," meaning not to permit anyone whom the husband dislikes to enter his house.