In order for you to have a marriage with this man that is recognized by the Catholic Church, you must approach your parish priest, who will speak to both of you, and explain to your boyfriend your obligations as a Catholic, and the reason why the Church feels these issues are important. Your boyfriend can also ask the priest any questions he wants about the Catholic Church. To be married to him, and in his Church, (which seems a bit odd if he is not really religious) the priest will request an indult, or special permission from the local bishop, explaning why you are seeking this permission.
Even if your boyfriend still wants to marry in his denomination, with a Catholic priest present to wittness the ceremony for the Church, at the very least it will be an opportunity for you to reveiw what your obligations to God are as a Catholic, and may expose him to the teachings of the Catholic Church. Many people dislike what they think the Catholic Church teaches, and not what the Church really teaches. So do approach your parish priest, and see what can be done.