Why is he so shy with me?

So we have a mutual crush i guess, when he is around he steals looks, stare from far and becomes extremely shy when i approach him. In his previous relationship he would hold hands of the girl and let everyone know that he liked his ex ( she left him). if he was so open , why is he so shy and silent with me? ( P. s i made the first step)
Why is he so shy with me?
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