All good answers here and I have one additional thing to add. Children get used to sleeping with a parent and that is a hard cycle to break. It must be broken as this may be now the biggest problem.
If you develop a loving night time routine and let them know they may not come into your room. If they do, walk them back to their beds, tuck them in, and leave. (No rewards like kissing them on the forehead, laying down with them awhile, etc.)
They may throw a total fit the first time or two. Be strong. Explain one time why it isn't good for you or them to have sleep interrupted this way and it isn't good for kids to sleep with a parent.
My daughter made this mistake and she was horrified how big of a fit her daughter threw. I just happened to come for a visit and we got her to not do this by telling her not to wake "Mimi" so Mimi could get her rest. SHe didn't want to throw a fit with her Mimi there. We explained that my being there sleeping by myself, mom sleeping by herself (dad works out of town a lot), and her sleeping by herself (with her white noise or ocean sounds) was the norm for everyone. She hasn't complained since.