All credit to you for wanting to be a team OP, and that's the way it should be when you're a couple, whether married or not. However, you are being a team, by splitting the bills and paying half each for food, etc, but then any money left over, if you have roughly the same amount, should then be down to the two of you INDIVIDUALLY to decide how it's spent. He chooses to spend his on beer etc., and it's totally up to YOU how you spend yours. It's not down to YOU to bail him out because he's already spent his 'fun money', 'allowance', whatever you choose to call it. He knows how much he has, and should by now have learned that once it's gone, it's gone!!
I suggest that you sit down with him and tell him that you are happy to go halves on all bills, rent, food, holidays, and expenses for your JOINT child/children, then you both keep what you have left over, to spend as you wish, for stuff like clothing, socialising, etc. However, HE must pay for HIS child out of his share, as by you paying for all the food, and him paying for his child, you are effectively paying half towards HIS child with another woman, which I think most women would think was unfair. You may be a team OP, but HIS child by another mother is NOT your responsibility. After all, if the shoe was on the other foot, ie, you were paying your ex maintenance for a child you had with him, would your current partner be happy to feel he was paying half toward that? I very much doubt it, and if he were to tell you he would, he's lying!