Re: Am i being an idiot? Is my husband mamma's boy?
It's a cultural thing. In his culture, the sons are the parents' retirement system. The daughters become part of their husbands' families. You should have known this before going into a marriage. He should have told you. Your sister-in-law, if married, will be responsible for her in-laws. A lot of cultures work this way. You would not, in his culture, be supporting and caring for your parents--you'd be taking care of his.
You're going to have to work this one out between the two of you and maybe a financial planner. This requires a budget that specifies exactly how much goes to them, when, and so on. You'll need extra for their emergencies as well as any you have. You need a written definition of what an emergency is, or a very clear verbal definition (is we can't pay the rent because we gave the rent money to a relative for a wedding an emergency? what about we gave it to the relative because he had to pay the doctor?). Then he needs to convey what emergency means to them. You can show your husband you understand the cultural issue and want to be supportive by insisting that he gets extra life insurance in order to be certain they're provided for if something happens to him. (Your insurance agent will be floored, but my husband was pretty pleased that I'd thought of it.)
It's tough being expected to support or contribute to the support of adults who ought to be capable of supporting themselves, or have saved for their old age, but that's the expectation some of us with intercultural marriages have to live with. Is it worth it to you to stay with him, given that this is not going to change, their health is going to deteriorate, and the demands on your husband will inevitably increase? I can't say.