Jackie, There are two rules that I followed in telling my family that have really worked, but I had to be the one to police the rules. 1) I never tolerate anyone bad mouthing my H. I don't do it. No one else can. 2) I never lean on them for support when things get bad. I just keep my mouth shut.
I know that last one in particular may seem wierd, when talking about family. Still it's important not to involve them in the marriage relationship. Complaining, bad mouthing, crying or openly anguishing makes it that more difficult to keep everyone on good terms.
When I first told my parents, my 77 year old Pop wanted to come out here and have a "man-to-man" talk with my H. I was pretty fiesty when I told my own father to stand down.
As far as I'm concerned, I'm the only one who has earned the right to hate my H, and until the day that I choose to exercise that right, everyone has to wait in line behind me.
I don't think there's anything wrong with telling your family, you just have to be strong enough to uphold the boundaries of your marriage.