You treated Benji like he was your own even though he Technically wasn't yours especially when you found out you were infertile. you're husband had cheated on you and Benji was the child of his mistress but neither we're suited to be parents so you decided to take care of him as his co-parent. He was yours in a way

You had taken Benji out to the park for some fresh air since you haven't been able to get out much when you saw a familiar face (how does your character look?)