I am a big Sims fan, and I have been playing my Sims games on ps2 for months but I still need HELP!?

I have gotten married but thats as far as I can get my love relationships to go! I havent been able to whoo hoo or cuddle in bed with another Sim. The romance part seems to be very hard. Can someone please tell me what Im doing wrong and what I have to do to get my married Sims to have ? I love this game but It is so frustrating when you can't get your married Sims to do more! There isno romance in my game! I can't go any further and I dont know what else to do! How do you win this game or end it? SOMEONE PLEASE HELP ME!