There's no such thing as "cheating" when people aren't married. There's just, "I'm also screwing some other guy/girl. Deal with it."
Eh, it’s mostly semantics. I usually use ‘cheating’ for boyfriend/girlfriend situations or when the level of ‘cheating’ isn’t physical yet, and ‘affair’ for married couples.
In any case, one has to wonder if the boy is even capable of fathering a child yet, as he seems to have all the physical maturity of your average 8-year-old - I’d sure like to see the results of a DNA test on that baby!