What do you think?

What do you think about Family? Well, family is important to me, but should you always side with your family, even over your spouse? Even if your family is wrong? Well, I have had a bit of a situation. I will agree, we were all at fault due to the fact we had all had a little bit to drink, but then things like this always happen. Here is, without telling the entire long story, what I am asking.
If a parent has adult children and a boyfriend the same age, who acts petty, jealous and very much like a baby and starts mess with your spouse, husband or wife, should you take your family's side just because they are your family, or should you choose to stand your ground on the side of your spouse, who was in the right? Isn't your spouse your family now, even above all the others?
My family has a bad way of believing in nothing but family. Or do they? I never get listened except by my grandmother when there is a problem. I voice my concerns for a long time about working with my sister at my mother's office where I have been working since I was 12 years old, and my sister jumps on me taking up for a guy, and I am an "idiot" for not being on her side, when the other guy, was 1) in the wrong in what he did, 2) is not family of any relation to us, 3) the other guy started crap, on purpose with my husband to cause a problem.
My sister physically attacked me for this in my grandmother's house.
I respect and love my grandmother very much. I did not want to tear up anything in her home. I got my sister in an MMA or Juijitsu style hold and took her to the floor to keep her from tearing up my grandmother's home.
Now, My mom, sister, and everyone else blames everything on my husband and treats the entire situation as his fault. THIS IS UNFAIR. Then they act as if I should be on their side instetad of my husband's side. NOT GOING TO HAPPEN.