Im really confused and dont know what to do?

im 19 and my cousin is 14 and we have allways been very close but about 3 years ago we were talking and i dont know how it happened but she asked me could she look at my nd then touch it and i agreed as the time went on we were experimenting every ual activity besides l and i confess i was loving it but always felt guilty after it i mean i never forced her to do it she would always consent we have kinda stopped now over the last 4 or 5 months and i constantly fantasize about wat we have done and so has she cause she told me and when i masturbate i think bout it all the time but the last three times i was with a girl i could not get a on a semi at most wat can i do to stop this because its ruining my self esteem and ual confidence but in the othe hand i love being with my cousin but i know its not right and i feel very confused