Am I wrong?

So my husband and his dad own a business together and his dad asked me to kind of be their receptionist because they’re super unorganized, but he said he can’t pay me. I’m a stay at home mom, I have an online job that I actually get paid for (it’s not much but better than 0 dollars) and I have a household and a dog to take of as well. I told my husband I don’t think I want to do it since I won’t get paid and he got pissed at me and said it’s rude I don’t want to help them make the business successful and that I’d help them make more money in the long run. I don’t think he realizes how full my hands are with a two year old alone + an online job and the house to take care of! Am I in the wrong here? Just looking for an outside opinion 😫