When my partner first moved up to live with me, we were both so excited about feeling what we did for one another, we didn't think too much about the practical issues of living together. Neither of us had lived with anyone for a long time; I, for one, had forgotten all the issues that arise when you inhabit space with someone else.
I had planned on having a little talk when I told him yes because I wanted him to understand, that although this is fine for now (more than fine, great even), at some point it won't be enough. As in, eventually, I want to get married. And while living together is all I need now, at some point, resentment for not having more will begin to set in.