I've been thinking... Why did Stacy leave Chase? It's never been confirmed exactly why. So here's my theory:
Anti. OK, OK here me out. What if Anti was already terrorising Chase before and Chase was alone with his kids at the time. Before the whole red room thing though.
What if his kids walked in on Anti terrorising their dad and Anti tried to go for them? Obviously Chase stopped him but when Stacy came home, his kids told her everything.
That made Stacy think Chase was not safe around the children. So she left him, then he developed depression and you know what happens next....
It is juts my dumb theory but oh well.
