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this stupid guy that i like has an annoying ex g/f
and now this guy is being annoying and i'm feeling embarrassed
my fall back plan is to avoid him for a few weeks or the rest of my life

Definitely!

He even told her, and she still harasses him
but then he goes and still encourages it by trying to smooth things over with her even though he knows he's not interested
and then he acts one way with me on one day and then completely uninterested the next

it has the telltale signs of player written all over it

I feel like such an idiot, I'm usually good at telling the difference between 'nice guy' and 'd**k'

maybe its because he's a close friend of one of my best friends
she had such a high opinion of him

Yeah! Better to feel down a couple of days then let it drag on.