Why does my husband have to sign the papers when my house sells when we weren't married when I bought the home?

Texas is a community property state, so even though you bought your house before you married your husband, he effectively became the co-owner of the house upon your marriage because any money he may have contributed to payments, upkeep, etc. would be his contribution to the home and thus community property. The house began as your separate property because you bought it before you married, but the moment your husband began contributing to the household, he gained an interest in the home. The house purchased in 2004 is more straightforward because you purchased that home during your marriage. In any case, your husband would need to sign on the closing documents for either house because those houses are a part of your community property as a married couple.