The moment he takes you for granted is the moment he also ends his friendship with you. I mean, after all the help you lend, he still chooses not to help you? How ungrateful.
Well, the positive thing that you realized from the situation was that you are capable of lending a hand to someone in need. You're a generous person. And I didn't say that you have to refrain from doing it but know how to discern a person whom you can trust and someone whom you can turn to if you need help.