Why Does He Like 2 Play Games With Me So Much???(Help With Boyz)?

One minute were talkin and everything was goin great i guess. he liked me alot, i could tell he cared alot about me because he's cousins told me he's always talkin about me out of randomness. Anyways so one day he says he asked out some random girl, so they went out for two weeks, and i asked why he dissed me for her, he said that i didint know sh!t because he might have felt bad for her because she liked him, but why didint he care about my feelings? he talks to my sister about me all the time and he said that he neva liked her and he misses me alot and he didint know that i was gonna get that mad and not wanna come back to him. but my sister thinks that he just asked the otha girl out to see how tight of a leash i was on, he was just tryin to make me jelouse....but idk. what do think, its bothering me so much. if he cared about me so much then why would he like to see me hurt?