When you say that you're supporting him, do you mean financially or emotionally? If it's financially, then I can understand the resentment, and I'd even call you out as not being very practical. You've known him since July, so 3 months? No way that there's enough a commitment there for you to be financially supporting this guy. He's 30, he made his bed, let him lay in it.
Now, if you mean you're only supporting him emotionally, I don't see the problem. His lack of money has no effect on what you earn. Take care of yourself. It's not like you two are getting married and he's going to drag you down because he's not good with money.
Bottom line, you've known this guy 3 months tops. If you no longer like him because of his issues, than dump him and move on. It's not like you two have built a life together. Heck, at 3 months you barely know him.