Quote from Ross in The One After Vegas
Ross: I'm not kidding. Look, I can't have three failed marriages. I can't, okay? I am not gonna be that guy.
Rachel: So what, we just stay married forever?
Ross: Okay, how- How is this going to affect you, really? I mean, you fill some form out once in a while, instead of checking the box that says "Miss," you check the box that says, "Mrs." It's right next to it.
Rachel: Okay. I'm sorry, you're right. You know what? We can stay married because I thought that the boxes were far away from each other.