Maybride may very well be right... in which case, you've got a LOT of work to do.
However, I will say this. If you want this marriage to work, you will need to learn to tell your mother to back the ^&%# off. I've been handling divorces for 15 years, and one of the primary reasons I've seen for divorce is parental interference because one party or the other didn't know how to tell his or her parents to back the ^@%#& off,
This is YOUR job, since she's YOUR mother.
What you say: Mom, please don't make me choose between you. I've made a promise to him, and if you make me choose I'm going to choose him. He comes first, and that's that. So if you don't stop badmouthing him, we're done. And then no matter what is going on or what you are doing, if she starts badmouthing him, you get up and you leave. Done.