You can even make them flirt a lot, but be warned: flirting only works if your sims have a certain amount of social recognition for each other. There are tons of social options in The Sims 2, from just chatting to telling dirty jokes. There are always opportunities to meet new sims! You can also have your sim visit a community lot during the day (like a gym), invite other sims to your house, or chat with sims on the computer. If you have the Nightlife expansion, your sim can meet other sims through a matchmaker or during a night of partying out on the town. Moving them into the same house isn't the only way to meet sims, though.

You can either create them within the same household as the original sim, or separately and move them into your original Sim's house (as long as there are less than eight sims already living on the lot). Its gender, appearance, or aspirations don't have an effect on whether or not the multiple marriage mod will work, so go crazy. Go to the Neighborhood screen and click on 'Create Sim.' You should go through this process as if you were normally creating a new sim. Make sure you've correctly installed the mod, and that you aren't going to break your game (or computer) by doing so. After all, jealousy can make for some fun (or at the very least, interesting) gameplay. It would also be beneficial to find a mod that prevents your sims from experiencing jealousy, but that's really your call. A simple google search for 'Sims 2 Multiple Marriage Mod' can lead you to some useful links.

Sims 3 polygamy mod