Not NTR for me, only slight interest from the MC, and from the sound of it the girl only thought of MC in platonic way. assuming the guy she went out with is also a nicely developed character then all's good for me .
NTR, for me is when they are already in a relationship and someone cheated or...
I'm guilty of having too much plan to read list. then sometimes i added novels to check out last week and wanted to recall what those novel were again, but it's buried into a pile of 100+ novel in my list...