Divorce is easy. But you have to make up your mind first and be absolutely positive that is what you want, and then go ahead find a lawyer. I think he will be very happy to know that his no-cooperation stance is just a joke once a lawyer is involved. Mom with very young child has some advantage of getting the major share of the joint custody. Sole custody may be hard.
If not, then it will be very hard on both of you to work out the differences and stay married. But that is not a legal issue anymore.