At the very beginning of the relationship, realizing that your young man - a sissy, have developed their own terms of your communication. They can be any as long as it somehow limits the influence of his mother on your pair, and later, perhaps, and the family. Agree on a strict adherence to these rules, otherwise your life will not be easy.
Not skandalte with his mom
Your odds will only worsen the situation. Get ready to give in, to ignore at the right time to be silent. Of course you can try to put his beloved mother in place, but it is unlikely to lead to something good. Most likely, she was angry with you more, because you - the one who "stole" her son.
Do not put yourself between the elect and his mother
Trying to protect a man from communicating with his mother, to fulfill her requests to prohibit or to follow the advice - a waste of time. If you want to become a barrier between him and her, find yourself an extra in this tandem. Sissy rather give up his beloved, than by a single mother.
Do not compete with it
His mother will always be better prepared, better get out and wash the dishes better to know what to do in any situation. Do not try to prove that something ahead of her. It is enough that you know his worth, and declare it to others is not worth it.
If you decide on a relationship with a mama's boy, you have to get used to the constant presence of a foreign woman in the house - physical and spiritual. History knows little of successful marriages with such men, but maybe you have a chance to change the situation, finding a common language with the main woman in the life of her husband.