What's different about being a wife?

So I've been going a bit nuts on pinterest with wedding ideas. The fact that my sister is getting married on August first isn't helping. There are so questions that are all directed at me, because as it seems I'm the authority on it. ^^ god knows why... I certainly don't.
All these wedding plans have made me think a lot about marriage and what it means to be married. What will change after we get married? We already live together and have for almost 4 years, we moved in together after about 3 1/2 months. We've had a dog together for 3 years on fourth of July. We've had joint finances for at least 3 years.
So what will change when we marry on our 5 year anniversary?
I think maybe it'll have that feeling of permanency. I take the "till death do you part" part of the vows very seriously! I feel that since divorce has been destigmatized (which I think is a great thing! Believe me!), people are more prone to just give up and throw the towel. I know that there are very good reasons to get divorced, and there are situations where I would consider divorce myself. On the other hand I know that marriages need work! And I know I will do my damnedest to work and make sure that this will be my one and only marriage!
The other thing that would change might be kids. That part won't kick in though, until after I finish grad school. When you spend that much time in school, you'll want to actually use it before having kids. So that will be a change, but not for a while.
I want to be able to be a good wife. I just worry that I won't be. What makes a good wife? How do I achieve that? I don't really have the best role models. My parents aren't really the best suited couple. My mother has a lot of baggage from her first marriage. Charlie's parents aren't together. My American grandparents should never have stayed together and I wasn't around my Swiss grandparents at an age where I would have seen how they were together and been able to learn from them.
When you search the Internet for advice there isn't really much. Or at least nothing that really seems useful to me.
I wish I had a support system. I don't really believe in religion, but I do envy the sense of community you can get from it.
What do I do if I mess up? Who do I go to for advice?