Those arent things that she can blame you for. Or if she does you can remind her that if she chose not to pay, the daycare could have sued her for nonpayment.
Also, you arent the bad guy for trying to save your M, you are the bad guy, for being you. Thats the only reason. She blames you for everything. If she stubbed her toe this morning she could figure out a way to make it your stupid fault. I know that from my personal exp. Everything for a while was my H's stupid fault. And I mean everything. It doesnt mean that she will always feel this way, or that shes right. But thats how she feels right now, and telling her that shes wrong, or trying to defend yourself just wont be productive right now.
I agree that losing your cool was bad, but eh, we all screw up sometimes. Time to move on.
I guess I gave the wrong finger to the wrong man...