Very well thought out and said B2Y.
There comes a time when one must be the responisble adult, and make intelligent decisions for those who can not, will not and/or who are incapable.
It seems that time may have come with respect to your situation, doydie.
IMO, You did the right thing...
Your MIL may not be able to 'get' that she hurt you, but I think that you have at least made it clear to your husband that you are not willing to participate in this sort of thing without limits.
Feeling that he needs to humor his mother is one thing...but he may benefit from being reminded that the whims of his mother need to be balanced with paying consideration to your needs and feelings as well

.
With love, Erika