i feel like this is about a few things..
probably about a girl who screwed things up.. and then he is trying to get back at her, hence "spread you like a disease." he thinks this girl is really full of herself- "i'm making a list of all your so-called 'big plans'" and he wants her to prove to him that she can just leave him/everything for these "plans." i think he also thinks that because she screwed up she needs to prove to him that she's changed.. "give me a reason just to see things through until the end because i'm on to you."
i feel like this is about a few things.. probably about a girl who screwed things up.. and then he is trying to get back at her, hence "spread you like a disease." he thinks this girl is really full of herself- "i'm making a list of all your so-called 'big plans'" and he wants her to prove to him that she can just leave him/everything for these "plans." i think he also thinks that because she screwed up she needs to prove to him that she's changed.. "give me a reason just to see things through until the end because i'm on to you."
that's confusing. just my take.