My predisposition to assume that an agent is male is stronger than my predisposition to assume heteronormative relationships. My immediate reaction to the sentence, "The agent's husband stood up from the table" was to suppose a male agent with a male spouse. But I'm probably unusual in this regard.
Couldn't you just default to "he" when writing, then when finished, flip a coin (or refer to whatever randomized gender generator you prefer), and go back and change the gender if need be? It wouldn't interrupt the work flow; it would just be a little work after to revise.