Well first of all, u can't give in! Doing this gives your child mixed signals and tells him that if he throws a fit or argues w/ u, that he will eventually get his way! And guess what? It's working for him! You need to put your foot down and put him in his bed and make him stay there! If he gets up, put him back down again and again until he eventually stays there. It will probably take a while (but u say u stay up late anyway, so...) and he will continue to try it for several nights, but after that there should be no more problems! You just have to stick to your guns, b/c if u give in now, he will grow up thinking that this is how things work, and it will become a BIG problem later, say anytime he wants ANYTHING, and not just w/ u! Also keep in mind that this is affecting your other child as well. She may see this as favoritism, that her brother gets whatever he wants, gets extra love and cuddles all night from mommy and daddy...I'm sure u can see how this could make her feel! That will start to cause other problems, like rebellion later on to try to get your attention or get back at u for it, trust me! Also, while you're trying the stay in your bed thing, u may also try something like staying w/ him until just after he falls asleep, and making him a deal that u will snuggle w/ him until then, but once he falls asleep he doesn't need u anymore b/c he's a big boy- lots of kids don't want to be alone in their own beds b/c there's no one to love on!