How many romantic interests do your Sims usually have?

I've made a few tries at the family side of The Sims but couldn't stay interested in it. When I get something new that has a woohoo action I eventually try it out but usually get bored with that after one or two goes at it. Had a few autonomous openings of the pink relations bar only for it to fade away. With a single exception all my sims have turned out to be real loners.