this guy keeps telling me to leave my boyfriend?

hes not literally saying leave him but he is saying he prefers me single. he is a pothead and smokes a lot. one day he came up to me and put his number on my phone. we hung out as friends but i could sense that he wanted something more. he tells me how cute i am and how hes sad i have a boyfriend and i should do something about it. he probably does this to other girls but why do i feel bad for him? he stopped texting me but why do i feel like i want to text him