After Feyre and Mor’s first argument, they talked and made amends. Mor admitted to Feyre that she preferred females…and she also told Feyre that she had been in love with you for centuries, but she knew you would never return her feelings…so she waited and waited and waited, and never committed herself to another…and silently wished one day, you would love her the same way she loves you…

You knew none of this, because Mor had kept it a secret from everyone…