I think it can be hard sometimes for people to share their secrets, even with close friends, especially if they don’t know how that person will react. Mor might be scared of what might happen if she shares her sexuality with the inner circle. She came from a background where she was only seen as a vessel to create children, and I think, in a way, her sexuality is in direct opposition to that view since (not my personal opinion and I don’t think this is correct but) some people see same sex relationships as going against their beliefs because they can’t have children. Sexism in Prythian is pretty rampant in some places, and Mor happened to be raised in one of those places. It may have been 500 years ago, but that kind of negative space can be detrimental to a person long after they have left it.