Should you move in together before marriage?

Is it true that if you move in and act like a wife, they will have no reason to marry you??

My boyfriend wants me to move in, and im planning to in the summer. I go over to his house often. I know his cleaning habits. We are like the same person and we know how to give each other space when needed, as we both like our alone time but also have a blast together But part of me is hesitant and worried about how it could affect our relationship. We know each others habits already and we hardly ever argue. We have a healthy relationship and good communication, long term type. We’ve been together almost 2 years. And he says he cant wait to make me his wife. I told him he has 4-5 years to propose and he said, “its gonna happen a lot sooner than that” lol.