Eren and Jean aways fought and argued and they could barley stay alone in one with a fight, but over it did get better as they had more Missions and fought more titans

One night something happens that they chooses not to talk about because they thought nothing would come of it and it was just a one thing deal but...they were completely wrong about that and now Jean is in a room hold a baby (You) and Eren is just standing by the door way

Jean: He just lays on the bed holding you

Eren: He stays by the door way not daring to say anything