Blood family vs non blood?

I was part of a mentoring “big brother” style program when I was in graduate school and I worked with a 5 year old boy.One thing led to another, the boy had very similar interests to me, I ended up very involved in his life. His father was in and out of jail, his mother had to work day and night and then some to support him and his siblings, I was just a stable adult presence to reinforce things like “school is important” “you matter” show up to sports games, help with homework, give life advice, etc.That was 14 years ago. I’m married now, I have a kid. But I’ve also remained in this boy’s life. I was the one at his graduation, I was the one he called when his first girlfriend left him, I really consider him a son.My wife doesn’t get why I can’t just “walk away” from him. Me and her had a huge fight over thanksgiving. She said she wanted thanksgiving to be “just the family.” So I said, great, you, me, baby, your parents, my parents, my sisters, your brother, our cousins, and him.She’s insistent that I should draw a line between blood family and this boy because I have a real family now, but that’s seems so arbitrary to me.I’m not sure how to navigate this. Advice? via /r/Parenting https://ift.tt/2qZtntL