You don't need a 3 month rule to find out if a guy likes you for you, or likes you for your body. If he comes back for a second and thrid date, he likes you. You need a 3 date rule, not a 3 month rule. Besides, what did you expect. Haven't you ever heard the saying "Why buy the cow when you can get the milk for free?" He is a guy, That is what some guys do. Believe me, the 3 date thing is long enough to know if a guy likes you.
not to be rude, but you used him just as much as he used you. you both got sex, i dont really see it as something worth being ashamed over but hey, its your life not mine.