Where there are three, there usually becomes two and one. You're being invited to be the one and with both the two having their own bond, their equity will speak together.
Not a startup founder nor do I really have much knowledge in dealing with equity, but assuming that 51% of the equity remains with OP, couldn’t they give the spouse “equity without executive power”? I know I’ve heard of that concept somewhere but can’t remember exactly where from.
Funny but true story. A guy and his wife tried to make me a tech. co-founder once (idea stage) and he was persistent that offering 33% to each is equal share :). Happy that I dodged that bullet.
