well ofcourse they have to like you as much as you like them, they have to be romantic interest and when there close and theres an option in the romance option that says Move in or something like that then you could. But I think it shows up randomly.
Chat with our AI personalities
You have to be partners with someone. Then you do your goal, I had to buy a bathtub, then the next goal was "get engaged" so yeah.
There is a app on the iPad called Sims Freeplay. It is free with in-app purchases but you can't get the sims 3 on the iPad.
FACEBOOK! Theres a sims app
Do it on the computer get the app
The Sims 1, 2, 3. Sim City, Zoo Tycoon ( same thing but with animals ) and The Sims Social ( Facebook app )