Please i need some help....?

alright i know this is wrong and i have tried to stop i have done everything in my power to make myself quit this and i just need some help. im not a bad person, i only want the best for people in life and i am blessed to have loving people around me everyday. i am blessed to have accomplished the things i have in my life and i don't mean to do this but... sadly i am a compulsive liar. its not BIG OUTLANDISH things, its little white lies that don't hurt anyone. for an ex. i don't want to go to a friends house and i don't want to be rude so i simply say " sorry girl but my mom said i cant go over." little things like that.. i have told big lies before.. one of them is : i was in boxing (not the lie part) i was pretty good at it, but to make myself look cooler i tell everyone im awesome at it. i don't mean to and i don't want to lie. the one person i lie most to is my fiance. one of the reasons is that im scared im not good enough so i make myself good enough, he has already caught me in a couple of lies... fights break out feelings are hurt and i don't want to lie anymore, but sadly i just cant seem to stop. i don't have the money to get professional help, and i don't know what else to do. im scared that if my lies don't stop ill loose my fiance and my friends. i really need some help!!! :'(