That is pretty reprehensible... isn't it common sense not to go on a plane when you test positive for COVID until you test negative again? That's putting other people in danger. I think your husband is resenting your family because they aren't showing concern to others. If I were him, I'd worry that they are not educated enough to keep my child safe. Your continued interaction with the family mist be stressing him out.
You need to have a heart to heart conversation with your husband and understand his perspective. I think his concerns are legitimate. He may prefer that your family stays more educated about how viruses spread annd will come around if they show they are making extra efforts to be safe . Even if they contracted it before, it doesn't mean they can't get it again and spread it (although possibly quicker recovery from feeling sick due to existing antibodies).