In her quests, when she go investigating Tenzin, first time you have to warn him about Pema, second time don't warn him. You will get her cheating route.
There is also a walkthrough attached. You can use it
Kuvira is one of those too. maybe you didn't unlock her scenes? you have to accept her in marriage to begin her events. Then walk around with her, sleep with her, if the choices are right, you can have a foursome with Kuvira, Korra, Asami as well
