O.W.
Hi K.-
My boys (almost 5 and 3) have been sleeping on and off with us for most of their lives. It started with my oldest son... we would get lazy with bedtime and do whatever was easiest, letting him fall asleep wherever, watching TV, etc. We created some very bad habits. When our second came along, we changed a lot. Co-sleeping is fine if it works for you, but since you wrote in it's obviously a problem to you so I'll tell you how we got our bed back once and for all!
I would have to say it's all about routine and consistency. We use timers in our house and that seems to work really well. That way, when the timer goes off, you're not the "bad guy." Our boys get their pajamas on and brush their teeth. We set the timer for 15 minutes and during this time, they get to lay in bed with us. We'll read a book, snuggle or goof around. When the timer goes off, they have to go sleep in their bed. This way, they still get that parent time in your bed, but the boundary is set. We still give them what they want (to sleep in our bed) but WE set the guidelines. Let me tell you, it has worked out great! They listen and understand the routine. We tell them beforehand the rules and sure enough, when that timer goes off, they say, "Now it's time to lay in our bed!" and we tuck them in. We haven't had a problem since.