What happens at home with Patrick and Erin when Harper returns? Why?

Harper returns home to find that Erin and Patrick have had a fight. Erin is at Harper's house with Drewe, and Patrick is parked just down the road from Harper's driveway. Erin still has not told anyone her and Harper's secret, but that action seems imminent. Erin comes to Harper, where he is sleeping in the office, and tells him she must find a way to live with it and move forward.