do what you feel like doing..most importantly dont think you are obligated to tell him or anyone else for that matter.its your personall life not theirs and its really none of their bussiness unless you want it to be.if you dont want them to know then dont let them know.and if they dont like it then lifes a bitch.i mean im pretty sure everyone has something in thier personal lives that they dont want other people to know and so they dont tell everyone.you never know about people.your dad might be totally fine with it.just do what makes you happy and you will always be happy..thats my motto