Mattheo was clear when he said he didn't want commitment. It was just s£x for him..that's why you never expected him to stay after you had his baby, surprisingly, he did. He was a good dad...he is sitting on the floor with the baby

"Don't do that" he tells him. His tone wasn't annoyed more teaching him right from wrong

no matter what mattheo shows up every week like clockwork to see him. Even if he leaves a death eater meeting early. The little boy looks up at him