Ah @cazzie. Are we talking about your stepson here? The autistic boy?
You say you want sympathy, I think. You are venting your anger or frustration and feeling a sense on injustice. Somehow the real mother has you as built in caregiver, and she knows she can “dump” her son with you at any time because you never refuse her. You won’t do that to the kid, I guess. And of course, your husband, the boy’s father, is no help. He’s usually not around and even when he is, he’s so disengaged he might as well be off in Beijing or something.
Well, it does suck. You have a soft heart, but are also not without your own health issues. You are fighting depression and I don’t know what else. The whole situation is wearing you down—husband, stepson, son, health.
Is it the unfairness that bothers you most? That it seems so unjust? Is it the work? Is it that she takes you for granted and never thanks you? Is it her apparent lack of concern for her son? Is it that she is cheating the system—taking government payments to care for the kid and then making you care for him?
Or is it that it is hurting your stepson—her son? Are you most concerned about him?
Or is it the impact on your life? That you may have to cancel plans for her convenience? Why are you willing to do this, @cazzie? I’m not judging you, by the way. I’m sure there are reasons that make sense to you.
So here’s some advice that may or may not be relevant.
When dealing with injustice, you can get yourself really bent out of shape with righteousness. However, unless you are prepared to pursue justice, getting bent out of shape is not helpful. We need to feel righteous in order to get the energy to pursue justice. But if we are not going to pursue justice, getting bent out of shape about it only hurts us psychologically. It is dangerous.
If you are not going to try to make this situation right, then I think it is best to not indulge your desire to feel wronged. Instead, you need to stay away from that feeling. Why? Because it puts you in danger of deeper depression. It helps you paint a picture of a world that is so wrong, you don’t want to be in it. It is an incredibly painful world.
I don’t think you need to make the world seem any more painful than it already is for you. I think you should change your story. I think (and this is true) that you are a heroine. I think the work you are doing with your stepson, if what you say is true, is heroic and wonderful. I think he is more your son than his real mother’s son. I think you care more about him than either she or your husband do.
I don’t think you can gain anything from beating her up. But I do think you can gain something from admiring your response to the situation. Forget the money. There’s no way to make that fair. Focus on your relationship with the boy and what you can build there. Think of every time she gives the boy to you as a gift. Be grateful to her instead of resentful. Thank fate that she is such a dipshit and is willing to give up her sons best years to you.
Yes, he is challenging, but you are up to the challenge and you are learning so much and you are able to help him because of your great empathy, something his mother doesn’t have. And you have this empathy, in part, because of your depression. You have been seeking meaning in life, and boy, here is meaning smacking you right in the face!
So that’s an alternative story. In this story, I have tried to make you a hero, and I don’t think I am wrong in doing that. Not that anyone could tell objectively, anyway, so you might as well be the hero of your own life. I want you to be happy, and being resentful doesn’t help. Feeling all kinds of injustice doesn’t help—except if you want to fight it. I do not sense that you want to fight it, and I don’t know how capable you would be, anyway. I think the better way to go is to think of yourself for what you are doing well and right; not focus on what she is doing poorly and wrong. I think that is healthier, both mentally and physically.