Most Helpful Girl
Oww... You missed very important details in your text! Your sister and this guy have a child together? I wouldn't try anything with a sibling's ex, let alone if they were together years and have a child. Personally, it would be very awkward to handle in the familia, esp with my own nephee ?!. What does your sister think about this?
I would stay out og any trouble. there are plenty of guys out there, not just your sister's ex!