As I understand from a little research on this subject, it will be difficult for you to become more of a priority for your husband. At most you can try to see the positive aspects. Your husband will likely always be attentive and considerate to your needs. (His mother’s needs might come first, but he will still pay attention to you.) You can also try to learn to be comfortable with his relationship with his mother and just accept it.
I would rather be married to a momma’s boy than to a physically or mentally abusive husband. Lastly, if you just can’t take it anymore, you can try a separation or divorce.