So a few months ago we just started lying down in his big bed with him and going to our own after he was asleep. We only had to do this for about a week and now he goes to sleep on his own. I'm going back to work next week and he just sleeps so much better with us. I sometimes have to lie down with him in our bed, but I don't think I'll intentionally let him sleep with us. If we have to do that to get more sleep and survive working days, we will.
Babies just sleep so much better next to mommy.
After all, you were all they knew for nine months. She can't get them to move back to their rooms since they have never slept alone. I think the master bedroom should be for mommy and daddy to have some alone time. This way the child becomes independent and knows that he has a room specially made just for him. If sleep sharing works for you, then continue.