Hi, check out any of the web sites for any of the cruise lines and you will see a number of them that have suites which either sleep up to 4 people or have 2 / 3 bedrooms to sleep up to 6 people.
They also have staterooms that can sleep up to 4 people but that usually entails either a sofa bed or 2 pullman beds (this means they fold down from the wall and you end up with what looks like 2 sets of bunk beds, one above the other. Not ideal unless you have small children plus the room is not as big as a suite so could be quite cramped.
You will need to look up the deck plans on the ships you are interested in. The deck plans are usually marked with a legend such as a star or a triangle or cross with a key denoting whether sofa bed or upper /lower pullmans (bunks) etc. If you are looking at a standard balcony consisting of double (twin beds put together) with a sofa bed, then depending on what sort and size of suite you are looking at make your choice. My personal concerns would be if you have the sofa bed option, then this is made up into the bed early evening, which limits your floor space - not a lot of room for 3 adults to get changed.