What does it mean when my husband wont go out alone with me anywhere? kids or MIL no matter what

There are too many possibilities, but I can guess that he wants you to always seem "unavailable" to other men... or he wants you to keep the children busy or his mother busy without putting in the work himself.

Oh so many reasons it could be. But first thing in mind for me is that he is ashamed of you in one way or another. He could also have a
Wandering mind/eye. Why don't you talk to him about it.

insecure control freak obviously, he needs to keep an eye on all his people all the time

means hes done or got a secret other life