If you and your husband do not have a problem with it, then leave it be. I would absolutely make the "advice" from mom stop. It isn't anyone else's business, but they only know when we complain. If you decide that you are fine with her coming in, then if mom asks how things are going just say "We got the situation resolved satisfactorily, thanks!"
If it is a problem for you guys, then just do not allow the cuddle time to take place in your bed, go to hers.
I have had two kids in my bed several times. I always sleep with my nursing babies, and sometimes the toddlers are not ready to be on their own every night. They DO grow out of it. From my 4 year old to my 18 year old, none of them are in my bed, just my 17month old.
You just need to do what you and your husband are comfortable with and refuse to allow family and friends to insert their opinions into your bedroom.
Read Dr. Sears for some back up. He has a great study he did on his own wife and children. Sleeping with mom actually regulates a child's breathing and may, in fact, prevent SIDS. Many, many more children die in their cribs than in their parent's bed, making the safer alternative in my opinion.