Yeah I agree with these people that say living together, but abstinence until marriage. You can get to know them enough that way to be sure you will be okay with them forever and that it's not just a physical relationship.
I would prefer to get married before living with my spouse. Being a Catholic, I do not believe in sex before marriage and if you want to live/sleep together, you should wed, assuming you love each other as well.
I lived with my now husbund first for one year to see how he lived and how we would get along. but I say make sure your love is very strong before you move in with them it will not be a walk in the park, though it does some times make your love stronger.