Taking emergency pill?

everytime me and my bf made love we don't use protection bec. he wants me to get pregnant but im not yet ready for that. im 24 and have stable job but im not ready to have my own family.What i did is i take emergency pill after we had . that was 2 times in a month when we do .I dont want him to know that im cheating by taking emergency pill.is taking an emergency pill often could harm my health?