Hi Op
I do think you and your husband do need some one outside family home,
to talk to about stuff like this in regard of your marriage problems,
Whether a good trustful friend ect or /and going for one to one counselling therapy sessions, then having couples relationships therapy too sessions,
I can see why as a family member his mother he turns to naturally,
the issue thing is which is Disrespectful is him talking within earshot of yourself,
Plus him slagging you off,
(Its obviously going 🙄 to be very much one sided about who's creating marriage disharmony, for obvious reasons,
Also if you hopefully can address sort out your marriage issues properly successfully,
His mother due to having a one sided viewpoint of his issues/faults with you is obviously going to have likely a negative jaundiced view of you going forwards,
However thinks work out in your marriage,
It's natural ,normal and healthy and human to want to vent/ talk through relationship problems just to get clarity, get reassurance