Both can be right in this case, according to the intention.
REMBMER*: When you use 'estar' to describe any characteristic of a person, normally you talk about impermanent states, which last for a while and then, they finish, for example moods: Está triste, está nervioso, está contento, está ansioso.
In the other hand, when you use 'ser (es in this case)', you talk about long duration characteristics (and I don't say permanent cause the person will die some day, lol), for examaple, physical characteristics, or types of personality: Es alto, es curioso, es atento.
But many times there will be situations where ser or estar are completely interchangeable, according to the intention that you wanna give, say 'rebel', or 'kind'.
You can say: 'Estás hecho un rebelde hoy', or 'Vaya, estás muy amable hoy' (You are such a rebel today - Oh, you're so kind today). An you will be talking about a specific situation.
And you can also say: Juan es rebelde. Marta es muy amable. (John is a rebel - Marta is so kind). And this will describe more about a habit of being in this person.
So, according to the rule, we can say, somehow, we can use both for being married, but 'es' would be more accurate.
Still, leaving the rule aside and talking from my perspective of native speaker, I can tell you: Both are used, both are perfectly alright, and they are interchangeable :)