Hello G. (I *love* your name, by the way).
My son is 2 1/2 years old. He still nurses; he still co-sleeps. I don't consider it a problem. If you are seeking time alone, then I think you've been given many reasonable options to address that, and not displace your son who clearly seeks that comfort from you for a reason. If you are coming to resent his presence, and want to push for him to sleep away from you, I really liked the suggestion about slowly moving yourself out of his room, closer to the door, out the door, behind the cracked door. Patience is the key, and the pay-off in the long run is huge. In my opinion, you can't teach him "your house, your rules". It's just brutish. He's two, he doesn't have the cognitive ability for that kind of reasoning. You have a 5 year old; she probably can't equate your desire for private time and sleeping in your bed. I wouldn't try to substitute a sibling for you either. It doesn't quite sit right with me to dump the expectation to provide nighttime care or comfort on a 4 or 5 year old sister. Inconvient or otherwise, you are the parent, not his siblings. It's not relevant how you got started with this behavior, so don't beat yourself up over it, or let someone else do it for you. You're here, look for a solution. If you find you can't make a permanent situation out of his sleeping in his own room right now, perhaps you can get him to accept a small pallet beside or at the foot of your bed, and gradually move him out that way. The bottom line is, he's two, he's clearly bonded to you, and still needs you in this capacity. It won't last forever, even if it is inconvienent for you and your husband. A need that is met goes away; a need that is not met, lasts forever.