It isn't wajib for one's parents to live with them. Yes, one can live with the in-laws however in many cases it has caused issues in marriages. It is your right upon your husband to have a comfortable home and your own privacy. Yes, he can perhaps get his mother to move closer if he wants to have a good relationship with her but it wouldn't be recommend for her to move in if this would cause you discomfort. This should be voiced to your husband that it isn't obliged for you to accept this if it may cause issues.
May Allah grant you success