Most of our knee jerk reactions are based on experience.
I think almost every one has a story where they pined after someone, they didn't reciprocate but they foolishly kept at it, because they thought if they were patient and a good friend, they'd think of them differently.
It could be totally different situation for Nave especially if he can "truly" just be friends.
But in my experience trying to be friends with someone, who you had feelings for and they didn't feel the same way, and there was a distance afterwards and then meeting up later and you're still single and no other prospects? Just seems to be picking up right where you left off.
And then say Nave becomes friends with her again and they spend time together, is it really that easy to say....well I can't afford to develop feelings for her.
Well you know how you can NOT develop feelings for her? By not being around her OR having someone else.