Is the husband considered a mahram, and if so, what is the definition of a mahram and how does that apply to the husband, or if he is not, how should he be dealt with?

A woman's mahram (definition) is someone whom she is eternally forbidden to marry. The husband is not a mahram by this definition, but he is considered as such in matters where a mahram is stipulated, such as a woman's travel. The purpose of stipulating a mahram is to protect and safeguard the woman, and the husband is more deserving of fulfilling this role. Jurists may differentiate between a mahram and a husband for further clarity.